H-Diplo/ISSF Policy Roundtable XII-1 on NATO Expansion in Retrospect

George Fujii Discussion

NATO’s enlargement after 1999 to include fourteen new member-states from Central and Eastern Europe remains among the most consequential and controversial policies of the post-Cold War era.  In an effort to deepen the debate over enlargement, we edited a special issue of the journal International Politics that included twelve articles by leading scholars representing a diverse array of thinking on the merits of expansion.[1]  A subset of those authors have written for this H-Diplo/ISSF roundtable, highlighting the continued interest in the topic.

Rather than attempting to arrive at an overarching judgment on the merits of NATO’s eastward move, the pieces in the roundtable and special issue instead tackle the merits and drawbacks of enlargement as it affected particular issues and actors.  This includes—but is certainly not limited to—the United States, Russia, NATO’s member states (old and new), and the alliance itself.  One major debate focuses on whether NATO’s expansion was the primary driver in the deterioration in relations with Russia, or simply one cause among many.  Taking the latter position, Stéfanie von Hlatky and Michel Fortmann write that it would have been irresponsible for the West to have ignored the strategic vacuum resulting from the end of the Cold War and the clamor from newly liberated states to join Western institutions. As they write, “With the benefit of hindsight, we can now see that the strategic imperative of integrating new countries into the Atlantic Alliance was glaringly obvious.”  Alexander Lanoszka echoes the point, noting that Russian democracy had already begun eroding under Russian President Boris Yeltsin, who shelled his own parliament in October 1993 and concentrated new powers in the presidency before the efforts to enlarge NATO moved forward.  He adds that given the arguments as far back as the early 1990s predicting a resurgence of Russian aggression, it seems hard to argue that NATO enlargement caused it.

In contrast, Rajan Menon contends that NATO enlargement was a significant (if not dispositive) factor in the downturn in U.S.-Russia relations.  Here, Menon takes the United States and its allies to task for not having enough imagination to develop a new framework for European security, as there existed after World War II. “Instead,” he writes, “the new order was built on the foundations of the old.” In a somewhat different vein, Kimberly Marten argues that it was not so much the addition of new members that threatened Russia, but rather the addition of new missions such as the 1999 Kosovo war and the 2011 war against Libya that created insecurities in Moscow. Still, within this, Marten proposes that U.S. deployments resulting from Bulgaria and Romania’s admission to NATO set off alarm bells for Moscow regarding Russian interests in the Black Sea region.  Surprisingly, the inclusion of those countries in NATO turned out to be even more threatening to Russia than the incorporation of Estonia, Latvia, and Lithuania, all of which border Russia proper, into the alliance.

Just as the contributors disagree over the impact on Russia and NATO-Russian relations, so too do the authors differ in their assessment of the impact of enlargement on European security writ large.  Lanoszka reminds us of the fears that existed for Europe at the start of the post-Cold War era, including Russian imperialism, German aggrandizement, and rampant security dilemmas.  “Amidst these prospects for nuclear proliferation, Russian revanchism, and dangerous nationalism,” he writes, “NATO enlargement thus was a reasonable solution to avert such disasters.” Adding new members to the alliance alleviated security contestation that might have arisen among states throughout the continent, which might otherwise have been uncertain of one another’s intentions.

Sara Bjerg Moller argues otherwise, pointing out that Eastern Europeans are still nervous about their security, regardless of their inclusion in NATO.  In fact, several have even asked that U.S. troops currently being withdrawn from Germany be stationed on their territories.  As she puts it, “The proximity of many of NATO’s newest members to Russia ensures that these countries will continue to experience insecurity for the foreseeable future.  Consequently, their appetite for additional NATO (and especially U.S.) military contributions is likely to be infinite.  No amount of troop contributions will satiate these countries’ security concerns for the simple reason that, while they may have joined what is frequently heralded as the most successful military alliance in history, their national histories and geography dictate that they will always fear Russia and feel insecure.”

The authors raise further concerns over the impact of additional members and new missions on NATO as an institution.  Moller notes that the alliance is not united against a single threat that focuses member states’ priorities as it was during the Cold War; in that sense, enlargement has reinforced and further undermined NATO’s cohesion.  To ensure that it is meeting the perceived security needs of all of its members, the implication is that the organization has to define security more broadly to include a range of threats, and risks greater fragmentation.  Along similar lines, Paul van Hooft proposes that the range of missions put great strain on defense establishments throughout the alliance, and the result was that “the armed forces of its European member states were becoming less capable of providing the deterrence that appealed to former Warsaw Pact countries.”  On a slightly more optimistic note, von Hlatky and Fortmann write that although “NATO enlargement was not a mistake, it was simply poorly executed, because the Alliance pushed through an unsustainable equation: making more commitments, and creating a steady flow of new members, all the while downsizing its overall military capabilities.”

Moving forward, a key issue will be whether the United States believes it must continue dominating European security affairs and, in turn, whether it views NATO as central to that purpose.  Like Moller, Van Hooft writes that because the U.S. sought to stay in charge of European security, enlarge the alliance, keep Europe from developing separate capabilities, and garner support of allies for U.S. missions far from Europe, it stretched NATO too thin and contributed to greater fragmentation. “The situation would arguably have been better for both Americans and Europeans,” he writes, “had NATO remained focused on its core military costs while the Europeans were encouraged to take on additional crisis management tasks.”

Taken as a whole, the pieces suggest future avenues for research, and the need for policy re-evaluation on the continued logic of NATO expansion.  The arguments in this roundtable are not meant to be the final word on the course, conduct, and implications of NATO’s post-Cold War enlargement.  Academic topics that remain understudied include different conceptions of non-NATO European security frameworks, the debates in the West and in Russia over whether a democratic Russia could be invited to join NATO, and the role that the China challenge is likely to pose for an alliance as expansive and diverse as post-enlargement NATO. As for policy, the nuanced merits and drawbacks identified here push Western analysts—especially in the United States—to grapple with the reality that enlargement has not been an unbridled good even if policymakers sometimes suggest as much.  At a time when continued expansion remains on the policy agenda for states such as Georgia and Ukraine,[2] strategists would thus be wise to critically assess the costs and benefits of adding still more members to the alliance and to compare those to the costs and benefits of not doing so. Just as NATO’s post-Cold War enlargement yielded mixed results, so too is its continued enlargement unlikely to be either a slam dunk or unmitigated failure. 


James Goldgeier is a Robert Bosch Senior Visiting Fellow at the Center on the United States and Europe at the Brookings Institution and a Professor at the School of International Service at American University, where he served as Dean from 2011-2017.  Previously, he was a professor at George Washington University, where from 2001-2005, he directed the Elliott School’s Institute for European, Russian and Eurasian Studies.  Before moving to Washington, D.C., he taught at Cornell University.  He has served as a director for Russian, Ukrainian, and Eurasian Affairs on the National Security Council Staff, and in 2018-2019, he held the inaugural Library of Congress chair in U.S.-Russia Relations.  He has authored or co-authored four books, including Not Whether but When: The U.S. Decision to Enlarge NATO (Brookings 1999); Power and Purpose: U.S. Policy toward Russia after the Cold War (Brookings, 2003), co-authored with Michael McFaul); and America between the Wars: From 11/9-9/11 (PublicAffairs 2008), coauthored with Derek Chollet).

Joshua Shifrinson is an Assistant Professor of International Relations at Boston University.  His research focuses on great power politics, alliance relations, and U.S. diplomatic history.  A graduate of Brandeis University and MIT, his first book - Rising Titans, Falling Giants: How Great Powers Exploit Power Shifts - was published by Cornell University Press in 2018.  His current book project examines the grand strategic debate over preserving U.S. unipolarity in the 1990s and early 2000s.

Paul van Hooft is a Senior Strategic Analyst at the Hague Centre for Strategic Studies and the Co-Chair of the Centre’s Initiative on the Future of the Transatlantic Relationship.  He is also a fellow at the Netherlands Defence Academy.  Van Hooft was a fellow at the Security Studies Program of the Massachusetts Institute of Technology from 2018-2020, originally as a Stanton Nuclear Security Fellow.  Previously, Van Hooft was a Max Weber Fellow at the European University Institute from 2016-2018, after he attained his Ph.D. in political science from the University of Amsterdam.  He received the 2016 dissertation prize from the Dutch and Flemish political science associations.  

Stéfanie von Hlatky is an associate professor of political studies at Queen’s University and Director of the Centre for International and Defence Policy (CIDP).  She’s held positions at Georgetown University, the Woodrow Wilson International Center for Scholars, Dartmouth College, ETH Zurich and was a Fulbright Visiting Research Chair at the University of Southern California’s Centre for Public Diplomacy in 2016. She has published a monograph with Oxford University Press titled American Allies in Times of War: The Great Asymmetry (2013) and four edited volumes, including The Future of US Extended Deterrence, co-edited with Andreas Wenger, (Georgetown University Press, 2015) and Countering Violent Extremism and Terrorism: Assessing Domestic and International Strategies (McGill-Queen’s University Press, 2020). Stéfanie von Hlatky is the founder of Women in International Security-Canada and co-host of the security and defense podcast Battle Rhythm

Michel Fortmann (Ph.D., Montréal) is associate professor of political science at the Université de Montréal.  He has headed jointly headed with T.V. Paul the McGill/U.de M. Centre for International Peace and Security Studies (CIPSS) since its foundation in 1996 until 2013.  He is the author of Les cycles de Mars.  Révolutions militaires et édification étatique de la Renaissance à nos jours, Economica, 2010.  He has written extensively and edited several books on defense policies, arms control, European security and strategic studies.  His latest publication is Le retour du risque nucléaire, collection « Le monde en poche » (Presse de l’Université de Montréal, 2019).

Alexander Lanoszka is Assistant Professor in the Department of Political Science at the University of Waterloo and the Balsillie School of International Affairs.  His research addresses alliance politics and military strategy, with a regional focus on Europe.  He has published in such peer-reviewed journals as International Security, International Affairs, and Security Studies.  His book Atomic Assurance: The Alliance Politics of Nuclear Proliferation (Cornell University Press, 2018) examines whether the United States has been as effective in suppressing the nuclear ambitions of its treaty allies as often claimed.

Kimberly Marten is a professor of political science (and the department chair) at Barnard College, Columbia University, and a faculty member both of Columbia’s Harriman Institute and Saltzman Institute for War and Peace Studies.  She has written four books, including Warlords: Strong-Arm Brokers in Weak States (Cornell University Press, 2012) and Engaging the Enemy: Organization Theory and Soviet Military Innovation (Princeton University Press, 1993), which received the Marshall Shulman Prize.  The Council on Foreign Relations published her special report, Reducing Tensions between Russia and NATO (2017).  In addition to her numerous academic journal articles, her policy pieces have appeared in the Washington Quarterly, ForeignAffairs.com, War on the Rocks, Lawfare, the Washington Post’s Monkey Cage blog, the Huffington Post, the New York Times, and the New Republic, and she was honored to testify before Congress in July 2020. She is a frequent media commentator and appeared on “The Daily Show” with Jon Stewart.  She earned her A.B. at Harvard and Ph.D. at Stanford.  She is a member of the Council on Foreign Relations and the International Institute

Rajan Menon holds the Anne and Bernard Spitzer Chair in International Relations at the Powell School, City College of New York/City University of New York, a Senior Research Scholar at the Saltzman Institute of War and Peace Studies, Columbia University, and a Non-Resident Fellow at the Quincy Institute for Responsible Statecraft in Washington, DC. He has been a Fellow at the Carnegie Council on Ethics in International Affairs and the New America Foundation, Academic Fellow at the Carnegie Corporation, Research Scholar the Kennan Institute, Woodrow Wilson International Center for Scholars (the Wilson Center), and Senior Fellow at the Council on Foreign Relations.  His two most recent books are Conflict in Ukraine: The Unwinding of the Post-Cold War Order, coauthored with Eugene Rumer (MIT Press, 2015), and The Conceit of Humanitarian Intervention (Oxford University Press, 2016).  In addition to publications in academic journals, he has written for Foreign Affairs, the Boston Review, Foreign Policy, National Interest, the New York Times Book Review, Los Angeles TimesNewsweekFinancial Times, Christian Science MonitorNewsdayChicago TribuneBoston Globe, US News & World Report, CNN, the Nation, and washingtonpost.com and appeared as a commentator on ABC, CNN, MSNBC, the BBC, NPR, France 24 Television, the Canadian Broadcasting Corporation, and Radio Australia. In 1989-90, while an International Affairs Fellow of the Council on Foreign Relations, he served as Special Assistant for National Security (focusing on arms control) on the staff of Representative Stephen J. Solarz (D-NY), chair of the House Foreign Relations Committee’s Asia-Pacific Subcommittee.

Sara Bjerg Moller is an Assistant Professor at the School of Diplomacy and International Relations at Seton Hall University in New Jersey.  Her current research examines the military effectiveness of alliances and coalitions.  She earned a B.A. (Distinction) from Queen’s University in Kingston, Ontario; a M.A. (Honors) from the Security Studies Program at Georgetown University; and a Ph.D. in Political Science from Columbia University.  Moller is the recipient of fellowships from the Massachusetts Institute of Technology, the Institute for Conflict and Security Studies, and the NATO Defense College.




Was NATO enlargement good for security?  The answer depends on who, where, and when.  Enlargement considerably benefitted European security in the short-term.  However, I argue that the long-term legacy for European security, for the organization itself, and for American grand strategy and security is less positive, because of how enlargement was implemented.

Enlargement did a lot of good.  Underpinned by the continued presence of American forces, it facilitated the successful unification of Germany, strengthened the stability and security of Central and Eastern Europe, and settled relations with Russia to the advantage of NATO and former Warsaw Pact members.[3]  In particular, the prospect and process of NATO enlargement in the 1990s and the 2000s, together with the parallel enlargement of the European Union, offered the Central and Eastern European states better options than they would otherwise have had.  As U.S. officials put it, the continuation of NATO and its enlargement allowed the U.S. to consolidate its Cold War gains and ensure (in President George H.W. Bush’s words) a Europe “whole and free.”[4]

Yet NATO enlargement was only one element of post-1989 American grand strategy, even when it came to American plans for Europe, and cannot be considered in isolation.  The U.S. also pursued a shift in NATO’s strategic concept towards crisis management and stability operations outside of the NATO treaty area.[5]  It wanted to use NATO as an all-purpose tool to spread stability, particularly in the Middle East and North Africa. To be sure, most European allies supported the change, though the French government was significantly less enthusiastic.  Consequently, European armed forces began an open-ended process of transformation away from the heavier forces needed for collective defense and deterrence towards lighter, expeditionary forces that were more suitable for the proposed ‘out of area’ operations.

The conceptual shift interacted with enlargement, specifically in the post-9/11conflicts.  Western European allies, along with aspiring new NATO members from Central and Eastern Europe, participated in Afghanistan and Iraq —though the latter was not a NATO operation —in large part to show support for the United States.  In doing so, they sought to ensure the continued presence of U.S. forces in Europe, and, in the case of the potential new members, to shore up American support for their membership.  Successfully managing the growth of NATO as an institution would have presented a challenge under the best of circumstances.  As it turned out, the strains of operations in Afghanistan and Iraq, in parallel with the transformation of the alliance’s armed forces and the integration into the structure of so many new members, used all the bandwidth of the European defense establishments. The stress was particularly pronounced for smaller states, which most of European allies are, with fewer resources than their much larger American ally and thus more limited capacity for adaptation.  The long-term effect undermined the actual capabilities of the alliance and its political support within European capitals and among the wider public.[6]

The third element of U.S. policy was the inhibition of attempts by key Western European states to form security institutions outside of NATO during the 1990s and early 2000s.  These included the revitalized the Western European Union, the French-German initiated Eurocorps, the European Security and Defense Identity within NATO, and the European Union’s European Security and Defense Policy.  These initiatives, all of which were intended to deal with the long-term insecurity that followed European dependency on the U.S., were triggered by the European failures in the Balkan Wars and American inaction in the early years.  Despite the fact that these institutions were intended for military operations that were separate from American strategic interests, U.S. officials perceived alternative European arrangements as threats to NATO, and viewed institutional competition as “zero sum.”[7]  The simultaneous enlargement of NATO was therefore convenient, as it allowed the U.S. to increase the transatlantic caucus within NATO, but also to weaponize the dependency of the new NATO members states so they would resist these initiatives.[8]

Why did the U.S. pursue these ambitious policies concurrently?  As noted by various officials, the apparatus was fundamentally Eurocentric and Americans were used to “running the show.”[9]  In the more constrained circumstances of the Cold War, the rush to expand the institution and its geographic scope would not have been possible. Yet with a vastly weakened Russia, a not yet ascendant China, and a divided Europe, the U.S. had free reign in post-Cold War Europe.  NATO enlargement was particularly seen in terms of a “closing window,” which was only available as long as Russia was weak.[10]  After the 1990s, U.S. priorities began shifting away from Europe, not only due to the post-9/11 conflicts, but because U.S. officials largely considered the process of consolidation of a Europe “whole and free” as complete and self-sustaining.[11]

The consequences of these policies toward Europe have become apparent, as successive U.S. administrations have become increasingly preoccupied with other developments, specifically the rise of China.  While the U.S. retains forces in Europe, the Middle East, and the Asia-Pacific region, in various ways it is signaling that it is no longer capable of upholding its commitments.  The 2018 National Defense Strategy reduced the defense planning assumptions from the objective in previous documents over the past twenty years to be able to fight in multiple regions simultaneously to the current ability to fight one war at a time against a great power.[12]  Given that China is increasingly being framed as the existential threat to U.S. interests,[13]  if the choice for US officials is between the Baltics and Taiwan, the outlook for Tallinn, Riga, and Vilnius is unpromising.[14]  Nor does addressing deterrence gaps through increased nuclear flexibility, as proposed in the 2018 Nuclear Proliferation Review,[15] comfort European allies. In fact, at the time when decisions on enlargement were made, little thought seems to have been given to the military consequences of the expanded commitments.[16]

Europe’s options are limited.  Kimberley Marten argues that Russia’s turn away from the West was overdetermined, and cannot be reduced to primarily enlargement.[17]  In turn, Alexander Lanoszka believes that the defense problems in Europe are manageable.[18]  Yet, it is clear that while the geographic reach of the alliance were being expanded, the armed forces of its European member states were becoming less capable of providing the deterrence that appealed to former Warsaw Pact countries. At the very least, the current situation constrains U.S. freedom of action should it want to shift resources towards the Asia-Pacific.  U.S. criticism of uneven burden sharing and “cheap riding,” particularly by Western European allies, is partly justified.[19]  Still, the U.S. actively discourages European efforts to improve their autonomous capabilities, and the security benefits of NATO membership shifted east even though the costs remained ostensibly equal for all member states.[20]  The Western European states that can afford to bolster deterrence have less incentive to do so, while the Central and Eastern European states that want deterrence have limited resources.

Unless they rapidly build their own capabilities, the Europeans now face the risk that they will become entangled in U.S. policies in the Asia-Pacific, as they previously were in Afghanistan and Iraq, simply to ensure continued U.S. commitment to European security. The situation would arguably have been better for both Americans and Europeans had NATO remained focused on its core military costs while the Europeans were encouraged to take on additional crisis management tasks.  The painful truth is that rapid NATO enlargement, combined with other key post-Cold War American policies, stretched the formula that had made NATO so successful to or beyond its breaking point.




More than twenty years after NATO began to open its doors to countries in Central and Eastern Europe, it is certainly appropriate to revisit scholarly debates about enlargement, which grew most intense between 1995 and the early 2000s.  Those debates raised important strategic questions about transatlantic security but were never decisively answered.  We return to some of those questions and argue that the strategic rationale for NATO enlargement was always sound and that its momentum was unstoppable.

First, as many observers have pointed out, NATO enlargement was not the work of only one state, however powerful it may be, but rather was a collective movement.  It was activated in response to the expressed desire of countries, from Bulgaria to the Baltics, to return to the West as a post-Cold War recovery mechanism.  From this point of view, it makes sense to consider the enlargement of the Alliance and the integration of these countries into the European Union as two sides of the same coin.  For Central and European countries, the European Union symbolized economic prosperity, while NATO implied protection and security against any resurgence of Russia.  This thinking is reflected in the words of the Lithuanian Ambassador to France, Giedrius Cekuolis: “NATO and the EU are like mother and father to us, and we cannot choose between the two.”[21] Indeed, the integration of Central European countries into both the EU and NATO created a unique political momentum that would engender lasting change on the continent.

Such a change did not necessarily appear inevitable at the time, however.  Some sharp criticisms of NATO enlargement were voiced by John Lewis Gaddis and George Kennan, who implied that enlargement would be a “fateful error” and one of the worst strategic mistakes the United States and its allies could make.[22] With the benefit of hindsight, we can now see that the strategic imperative of integrating new countries into the Atlantic Alliance was glaringly obvious. The dissolution of the Warsaw Pact and the fragmentation of the USSR created a geopolitical vacuum in the centre of Europe.  It was not in NATO’s interest or, indeed, of any of its member states, to allow this vacuum to evolve in unpredictable ways.  Was there not a risk of recreating an unstable and conflict-ridden situation similar to that the inter-war period? Was there not a risk of Russia regaining a foothold in a region that it has regarded for over a century as its preserve?  This strategic vacuum in central Europe needed to be secured, and opening NATO’s door to these countries appeared to be the best solution.  NATO enlargement was not a mistake, it was simply poorly executed, because the Alliance pushed through an unsustainable equation: making more commitments, and creating a steady flow of new members, all the while downsizing its overall military capabilities.[23] As Andrew Michta notes, “While scholars and analysts continue to debate the actual scope and phases of the process, few seem to question its overall political utility.”[24] There simply were no better alternatives at the time.

Even with a clear case and momentum in favour of enlargement, certain risks were apparent, especially in the management of NATO-Russia relations.  NATO has been blamed for antagonizing Russia, but while it is true that President Vladimir Putin's Russia has once again become fundamentally hostile to the United States and the West, NATO expansion had little to do with Russian antagonism. There are much more important causes of the decline in relations between Russia and the West.  Indeed, the humiliation of the break-up of the Soviet empire was not caused by the Alliance, nor were the economic chaos that Russia experienced in the 1990s and the endemic corruption of the elites.[25] The shift to the right in Russian public opinion, including growing hostility towards the West, preceded the enlargement of the Alliance by several years.[26] Alliance enlargement symbolized the humiliation of the former superpower, but it must be stressed that the causes of Russia's authoritarian turn and of what some call the new Cold War must be sought elsewhere.

Russian antagonism nevertheless forces NATO to once again re-appropriate the principle of collective defence against its traditional enemy in the East.  This, of course, must be done in the context of a Europe which has been politically fragmented by the rise of populism and weakened by three decades of defence cuts.  It is perhaps worth recalling, in this context, NATO's remarkable longevity and its ability to survive changes in the international order for 71 years.  Why would an enlarged Alliance be less able to meet the challenges of the twenty-first century?  In response to the new challenges on its Eastern flank, NATO has decisively embarked on a transformation process aimed at enhancing its deterrent capabilities against Russia and signaling Alliance cohesion in the process.  There is no reason to despair, provided, of course, that the United States assumes leadership of the Alliance again in 2021.



One criticism increasingly made of NATO is that its enlargement in the post-Cold War period has been a profound strategic blunder.  Joshua Shifrinson writes that U.S. strategists should “minimize the fallout from three decades of NATO enlargement that has left the United States exposed in an increasingly conflictual Europe.”[27] John Mearsheimer argues that “NATO expansion into eastern Europe” reflected an effort to develop a “liberal international order” with a “crusader mentality,” and thus in the process incautiously antagonized other major powers that are not liberal democracies.[28] Stephen Walt quotes George Kennan approvingly in describing NATO enlargement as a “tragic mistake.”[29] Paul van Hooft alleges that NATO enlargement “diluted European strategic cohesion.”[30]

Such assessments might seem valid when we scan the news headlines these days.  NATO is beset by internal squabbles and divergent threat assessments.  Russian leaders routinely invoke NATO enlargement as a source for their alleged insecurity.[31] Even before COVID-19 began to ravage the world, the security situation in Europe seemed to be at its lowest point since the Cold War ended, with NATO being a contributing factor because of its alleged role in instigating conflicts between Russia and its neighbors Georgia and Ukraine. Yet was NATO enlargement truly a bad thing?  As awful as things may appear in 2020, can we really hold NATO enlargement responsible for Europe’s current woes?

In a recent International Politics article, I argue NATO enlargement has in fact greatly benefited European security.[32] I believe that our frame of reference should not be what we observe in Europe today but rather what many well-informed analysts expected to have befallen Europe in the early 1990s. In changing our aperture, we find that our present—difficult as it may be—is arguably much better than predicted.

Indeed, many warned of numerous challenges that would tear asunder post-Cold War Europe.  John Mearsheimer foresaw in 1990 a grim future for Europe.  With neither U.S. nor Soviet forces to keep a lid on local fear and suspicion, “the best new order would incorporate the limited, managed proliferation of nuclear weapons.” Weaker states would “find it difficult to balance against German aggression” and that the Kremlin “might eventually threaten the new status quo” given how the “historical record provides abundant instances of Russian or Soviet involvement in Eastern Europe.”[33] Other scholars also expressed concern over widespread turmoil. Thinking beyond the Yugoslav Wars that had already been waged for several years, Stephen Van Evera cautioned that “[t]he risk of large scale violence stemming from the now-rising tide of Eastern nationalism is substantial.”[34] Policy-makers expressed similar anxieties. State Department official Charles Gati worried that relatively young democracies like Poland were fragile—a fear shared by some leading think tank researchers at the time.[35]

Amidst these prospects for nuclear proliferation, Russian revanchism, and dangerous nationalism, NATO enlargement thus was a reasonable solution to avert such disasters.  In addition to retaining some U.S. presence in Europe, as the United States ended up doing, incorporating former Soviet bloc countries in the same alliance as a reunified Germany would help mitigate security dilemmas that might otherwise ensue.  By fostering military-to-military contacts as well as providing security guarantees, NATO membership diffuses tensions on the continent by alleviating the insecurity that might come when states are uncertain of each other’s intentions.  Moreover, if Russia were to have posed a long-term threat because it would eventually revive its military power, as Mearsheimer and others have suggested, why postpone NATO enlargement?[36] Indeed, NATO enlargement critic Michael Brown argued that a valid criterion for enlarging NATO would be if a prospective member came under direct military threat by Russia.[37] Yet, in conceding this point, Brown overlooked how waiting for such a threat to materialize might be counterproductive. After all, NATO members might fear that by extending an alliance commitment in such circumstances they would undesirably be persecuting the border disputes and wars of others.  Such is why, in part, Georgia and Ukraine remain outside the Alliance to this day.[38]

Some might still claim that NATO enlargement has undermined democracy in Russia and encouraged Moscow to adopt a more aggressive posture, thus undermining U.S.-Russian relations over the long term.  This claim is also questionable.  Assertions of executive power by Russian president Boris Yeltsin—especially during the constitutional crisis of 1993—undermined the quality of Russian democracy before NATO enlargement was even publicly discussed.  Grievances about NATO enlargement were largely restricted to the foreign policy elite, whereas surveys reveal that voters for President Vladimir Putin made their choice based on the belief that he was pro-Western and not nationalist.[39] Most tellingly, Putin continued to  pursue a cooperative relationship with NATO countries despite the Alliance’s enlargement, going so far as to say that he had “no concerns about the expansion of NATO ... Today’s threats are such that the expansion of NATO will not remove them.”[40]

Of course, NATO enlargement is no panacea to Europe’s problems.  Some degree of conflict is inevitable within Europe given the socioeconomic, ethnic, and political diversity of its peoples.  Moreover, Western countries have made critical errors with Russia.  Insistence over deep structural adjustment reforms was a contributing factor to the economic and social traumas of the 1990s. NATO’s 1999 unilateral airstrikes alienated Russia in part because of the lack of direct consultations.[41] Threat perceptions do vary within the Alliance as a consequence of its enlargement. Nevertheless, that twenty-three countries participate in the enhanced Forward Presence (eFP) mission in the Baltic littoral region suggests that NATO retains more solidarity than often credited.  Indeed, the eFP mission suggests that, despite the expansion of commitments entailed by enlargement, deterrence of Russia may not be as expensive as often asserted.[42]

Even in our tumultuous times, we have not seen the nuclear proliferation and ethnic conflict that some observers expected in the early 1990s.  We have seen Russian revanchism, however, but those who would later criticize NATO enlargement for provoking Russian aggression had already anticipated it.  Europe remains much more cohesive than what was the case in the Cold War or the scenarios forecast by Mearsheimer and others. Far from being a “tragic mistake,” NATO enlargement has greatly benefited European security.




Did NATO’s geographic enlargement create or exacerbate a security dilemma for Russia?  The literature on that question is mixed.  Alberto Priego says yes, unequivocally, and claims that NATO made it worse with each new round of enlargement.[43]  Rajan Menon and William Ruger are more measured, recognizing that no single factor can explain conflict between Russia and the West, but they write that enlargement “helped increase” the security dilemma for Russia.[44]  Samuel Charap and Mikhail Troitskiy instead call the situation an “integration dilemma” in which one state is excluded from regional integration initiatives that are open to its neighbors and perceives the result in zero-sum terms, leading to the formation of competing regional blocs.[45]  They term this a “variant” of the security dilemma or “analogous” to it. Simon Duke and Carmen Gebhard argue that an integration dilemma is less intractable than a security dilemma, but find a “resemblance to a classical security dilemma” for Russia in NATO enlargement, while cautioning that an answer is complicated by Russian President Vladimir Putin’s tendency to talk in security threat terms more to domestic audiences than to foreign ones.[46]  Andrew Kydd suggests that NATO’s criteria for new membership (which limited it to states that are democratizing, have civilian control over the military, and have settled their ethnic and border disputes) may have “mitigated” the security dilemma for Russia by demonstrating that NATO’s goal was political, not simply anti-Russian expansionism; but he was writing in 2001, before the more recent tranches of enlargement, and warned that further enlargement might breach Russia’s threat threshold.[47]  In contrast, Andrey A. Sushentsov and William C. Wohlforth argue that both NATO and Russia were revisionists, not security seekers, creating an “offensive spiral” rather than a security dilemma. They add, though, that “the spiral contains elements of security-dilemma logic because each side sincerely believes that its definition of security is not intended to threaten a reasonable definition of security on the other side.”[48]

My own answer to this question, based on my prior empirical research (which I lack the space to present in any depth here),[49] uses Shiping Tang’s well-reasoned and comprehensive definition of the security dilemma.[50]  A security dilemma exists when two states in an anarchical system are defensive realists who do not have “malign intentions” and are not “intentionally threatening,” but face “uncertainty” about each other’s future intentions, and hence become locked in a race to accumulate more and more power. Tang’s definition differs from the one that Sushentsov and Wohlforth use (even though they cite him) because it emphasizes malign, not revisionist, behavior.

This distinction matters because even a revisionist actor can work hard to demonstrate that it is not malign and not threatening.  As Charles L. Glaser points out, a state can signal its benign intentions using “restraint in building military forces to reduce the adversary’s concern about its greediness.”[51]  Glaser credits Robert Jervis’s classic treatise on the security dilemma for introducing this crucial addition to realist definitions of threat: a focus not on power per se, but on military capabilities and the ability to fulfill particular (either offensive or defensive) military goals.[52]  A state (or alliance) can increase its relative power in the system without deploying military force that threatens the existence or well-being of other states. Stephen M. Walt draws on this to differentiate between the balance of power and the balance of threat, contending that offensive capabilities and intentions are crucial factors in threat assessment.[53]

Based on these definitions and distinctions, my answer to the question about whether NATO enlargement caused or contributed to a security dilemma for Russia is mostly no: NATO’s inclusion of the Visegrád states (Poland, Hungary, and the Czech Republic) and the Baltic states (Estonia, Latvia, and Lithuania) did not create or exacerbate a security dilemma for Russia. The answer switches to ‘maybe,’ though, when it comes to NATO’s inclusion of Bulgaria and Romania.

The key terms here are ‘uncertainty’ about ‘malign intentions.’ NATO (and the U.S.) were revisionist in the sense that they took advantage of the collapse of the Warsaw Pact in 1990 and of the Soviet Union in 1991 to expand their own political influence in the region.  But they did not cause either of those collapses, and enlargement happened years afterwards because states formerly under the Soviet thumb pressured NATO to let them in—not because the U.S. or NATO pressured them to join.  Enlargement per se did not signal aggression.

Most important, a review of the military capabilities that new NATO members brought to the table shows their inclusion weakened NATO, rather than strengthening it.  Let me give just a few examples.  In the years after Poland joined NATO it was mired in civil-military struggles and domestic political fights over budgeting and force planning, with no real plans even for territorial self-defense.[54]  Just before the Russia-Georgia war broke out in 2008, Poland officially defined its military missions primarily in terms of helping NATO and the UN in out-of-area peace enforcement and anti-terrorism operations.[55]  In another example, not only have force deployments in the Baltic states never been anywhere close to posing an offensive threat to Russia, but a famous 2016 RAND study found that NATO would have difficulty reinforcing their defenses either by land or sea in the event of a Russian attack.[56]

Meanwhile the U.S. force presence in Europe declined precipitously.[57]  This means that if NATO ever changed its military goals to the offense, for example by placing significant new weapons and personnel numbers in Europe, Russia would have plenty of advanced warning. Unless that occurred there could be no real uncertainty: NATO’s military capabilities and goals in the region were not malign, but only minimally (and even weakly) defensive, and could not have been used offensively.  Russia knew this.  According to data that Moscow released via the Vienna confidence-building agreement to other members of the Organization for Security and Cooperation in Europe, the number of troops and equipment (including battle tanks, armored personnel carriers, and artillery) that Russia deployed in its Western and Southern Military Districts (bordering NATO) from 2000-2010 dropped steeply, and continued to decline more gradually until a sharp uptick associated with its intervention in Ukraine in 2014.[58]  Indeed a recent RAND deep dive into Russian military doctrine discovered that the “critical force correlation” for Russian military planners is NATO’s ability to carry out an aerospace attack, based on air- and sea-launched precision strikes, with ground forces used primarily to mop up afterwards.[59]  The vast majority of those strikes would not be launched from the territories of new NATO member states, but from North America, the UK, and the open ocean.

Why, then, are Bulgaria and Romania different?  Their military capabilities were (and are) incapable of offensive action.  But Russian military planners might have begun to fear being suddenly denied naval access out through the Black Sea and into the Mediterranean, given that the only other non-NATO states on the Black Sea coastline were now Ukraine and Georgia.  Uncertainty for Russia may have been exacerbated in 2005-2006, when the U.S. signed agreements under the Eastern European Task Force framework to rotate 1,700 U.S. personnel through Romania and 2,500 through Bulgaria, with facilities upgrades in each country.  While the specific troop numbers and plans did not give the U.S. or NATO malign or offensive capabilities, the facilities upgrades in particular may have introduced uncertainty about NATO’s long-term intentions. Some analysts believe their presence helped motivate Putin’s infamous anti-Western speech at the Munich Security Conference in 2007,[60] when for the first time he called NATO enlargement “a serious provocation that reduces the level of mutual trust.”[61]

It may not be a coincidence that Georgia and Ukraine were where the Kremlin decided to wage war in 2008 and 2014.  In part Moscow may have decided to create “frozen conflicts” in each state to ensure that they never fit NATO membership criteria—although those criteria are subject to political negotiation, and hence to change.  Probably even more central to Russian military thinking, then, is the fact that through these operations Russia gained access to significant new chunks of the Black Sea coastline for its forces that are now based in Abkhazia,[62] and especially through its occupation of Crimea.[63]  It may also not be a coincidence that Russia has recently been targeting Turkey (and its Black Sea straits) for military cooperation, in an effort to undermine NATO unity. (Of course, through its aggressive military actions against NATO neighbors Georgia and Ukraine, Russia certainly did create or exacerbate a security dilemma for NATO.)

What probably threatened Russia most of all, though, was not NATO’s geographic enlargement, but its mission enlargement.  There was a growing U.S. tendency not to consult Russia in advance about its security activities, and to ignore the United Nations Security Council (UNSC) and its potential Russian veto.  The U.S. and UK launched airstrikes against Iraq in 1998, and even worse (given Russian ties to Serbia) NATO launched airstrikes against Serbia over the Kosovo conflict in 1999 without seeking UNSC support.  Then the U.S. led a coalition into war against Iraq in 2003 despite its failure to garner UNSC authorization.  Finally, in 2011 NATO’s UNSC-authorized mission to establish safe havens for civilians in Libya quietly morphed into a regime change operation, violating assurances made by U.S. President Barack Obama’s administration to Russia that this would not happen.[64]  U.S. unilateral abrogation of the Anti-Ballistic Missile Treaty in 2002 was also a blow[65]—not because any of these things took away from Russia’s ability to deter airstrikes on its own territory and defend itself with its huge nuclear and conventional arsenal, but because all of them reinforced the willingness and ability of the U.S. and its allies to sideline Russian global security concerns without consequence.

The threat that mattered most to Putin’s Kremlin was not one to Russia’s survival or well-being, but instead the threat to its regional and global influence and pride.  The sore point was Russia’s declining status in the world, and the fact that the United States could do as it pleased without taking Russian objections into account.  NATO enlargement symbolized Russia’s lost status and inflamed these concerns—but that is conceptually different from creating or exacerbating a security dilemma.




NATO did not dissolve after the Soviet Union imploded and the Cold War ended.  Instead, the alliance expanded, in stages—from 16 members at its Cold War peak to 30 in 2020.  While there was much early talk about a post-Cold War order, in Europe it eventually amounted to expanding the membership of two existing organizations: NATO and the European Union (EU).  Beyond that, it is hard to discern anything that could reasonably be described as a new security order, one comparable, say, to what the United States created after the end of World War II. Instead, after 1991, the United States’ approach to Europe served its primacist grand strategy while avoiding any reckoning with the dramatic changes in its security environment and the world.

The Russian government was uneasy about the enlargement of the EU and was particularly concerned about the Eastern Partnership, which was focused on deepening the EU’s ties with six new states that emerged from the wreckage of the Soviet Union.  But Russia’s concerns about this EU initiative paled before its aversion to NATO expansion.  Moscow was understandably perplexed that the West would, on the one hand, declare the Cold War to be over and welcome Russia as a partner, while simultaneously expanding what was arguably among the premier symbols of the Cold War rivalry toward its border. Had the circumstances been reversed, and the USSR, having won the Cold War, started moving the Warsaw Pact westward and eventually into Central America, all the while hailing the end of the Cold War and praising the United States and Western Europe as partners, the West would scarcely have reacted with equanimity.

Yet this does not get much attention in the prevailing account of the quarrel between Russia and the West, which proceeded roughly as follows: the root of the problem was not the decision to expand NATO but rather the conduct of the Russian state after Vladimir Putin replaced Boris Yeltsin as president in 2000. NATO expansion, according to this interpretation,[66] became a source of contention between Russia and the West because Putin created a nationalist and authoritarian political order and, as part a necessary part of that enterprise, depicted the West as an adversary. The standard explanation has a corollary: because cooperation between Russia and the United States broke down on account of the end of democracy in Russia, there can be no realistic prospect of a productive relationship, to say nothing of a partnership, with Russia until it becomes a democracy. This claim, which accords with the worldview of those associated with the liberal theory of international relations, conveniently absolves the United States and its European allies of any responsibility for what some have called the second Cold War.

This is a deeply flawed interpretation.  To start with, NATO expansion was never acceptable to Moscow, under any of its post-Cold War leaders.  In the 1990 settlement that led to the integration of a unified Germany into NATO, the Soviet leadership did not complain about NATO expansion; that project was not yet on the horizon, and there was, therefore, nothing to protest. Yet Soviet President Mikhail Gorbachev gained an assurance from the alliance that non-German troops would not be deployed on the territory of the former German Democratic Republic (GDR).  That should have made it clear, once NATO expansion began moving from concept to reality, that the leadership of the Russian Federation would not regard the alliance’s movement toward its borders benignly.  If Moscow wanted non-German NATO troops banned from eastern Germany, how likely was it that it would find NATO’s incorporation of other states of the former USSR acceptable?  Seen from this perspective, the debate over whether Gorbachev was in fact given a categorical assurance that NATO would not be expanded is beside the point.  No such commitment was given because no such initiative was then on the West’s agenda.  But Russia would have opposed NATO expansion whether or not there had been a pledge to eschew expansion. Even a brief look at the historical record shows that great powers rarely, if ever, take kindly to rivals’ alliances extending into areas they regard as vital to their security.

But one need not rely on logical deduction and inference or historical ruminations to reach this same conclusion.  The record shows that once serious discussions on expanding NATO eastward began, Moscow made its unequivocal opposition clear.  Russian president Boris Yeltsin’s first Foreign Minister, Andrei Kozyrev, did so, despite his reputation in the West as a leading liberal committed to forging a partnership with the United States and Europe.  So did Yeltsin—on more than one occasion.  Yeltsin’s Russia grudgingly accepted NATO expansion not because it was a democracy that shared common normative ground with the West.  It was simply too weak to have resisted.  Between 1990 and 1999, Russia’s economy contracted by 45 percent and the population plunged into penury.  The once-mighty Red Army was in shambles.  Russia depended on Western-dominated financial organizations to save it from economic implosion.  In short, the country was on its knees.

After 2000, Russia’s feeble democracy was replaced by an authoritarian political order; but what made NATO expansion an increasing source of tension between Moscow and the West was the resurgence—thanks in large measure to skyrocketing price of oil, a principal source of Russia’s export revenue—of the Russian economy and the emergence of a strong, centralized state. In short, once Russia was in a position to stand up and push back it started to do so.

The Russia-Georgia war of 2008 and the 2014 crisis in Ukraine made it clear that the balance of power had shifted.  Neither of these conflicts can be attributed solely to Russia fears that Georgia and Ukraine would eventually become members of NATO.  That would be an oversimplification.  Russia had been deeply involved in shaping the politics of these two countries even in the 1990s.  It was under Yeltsin, of course, that Abkhazia and South Ossetia seceded from Georgia, and with Russia’s help.  But it is no less simplistic to claim that in 2008 and 2014 NATO expansion was simply a Russian ruse for dominating its two neighbors.  Though neither Georgia nor Ukraine was given a Membership Action Plan (MAP) at the end of NATO’s 2008 Bucharest summit, the conclave’s closing statement stated explicitly that the door to membership in the Atlantic Alliance was open to both countries.  “NATO,” it said, “welcomes Ukraine’s and Georgia’s Euro-Atlantic aspirations for membership in NATO,” adding that “MAP is the next step for Ukraine and Georgia on their way to membership.”[67] 

So while NATO enlargement alone did not cause the deterioration of U.S.-Russian relations, it did contribute significantly to that outcome. One could ask, so what?  Perhaps the price was worth it.  Champions of NATO expansion aver that an enlarged Atlantic alliance has maintained the peace in Europe and promoted democracy in East-Central Europe.  But this assessment assumes that expanding NATO was the only way to maintain peace in post-Cold War Europe, even though Russia was, in the 1990s, hardly a threat.  There may have been other paths to a stable and inclusive post-Cold War settlement, but no attempt was made to create a new pan-European security order that extended from the Atlantic to Urals and included Russia.  Gorbachev certainly intimated that he favored such an approach by speaking of “a common European home.”[68] And Yeltsin, for his part, warned President Bill Clinton that expanding NATO would merely deepen the division of Europe.  Moreover, both Yeltsin and Putin even broached the subject of Russian membership in NATO.

The idea that a new European security order could have been created after the Cold War is not fanciful.  After World War II, American leaders did precisely that, with Marshall Plan (which helped reconstruct war-shattered Western Europe) and NATO (which guaranteed its security) serving as its pillars.  Nothing of equivalent boldness and creativity was attempted after the Cold War.  Instead, the new order was built on the foundations of the old.

The states of East-Central Europe that pushed early and hard for NATO membership, notably Poland, certainly wanted to hedge against the possibility of a revived and hostile Russia.  And given their history, they had good reason to worry.  Yet American advocates of expansion were not simply responding to these states’ requests for protection; they were looking for ways to sustain NATO.  This was not easy.  After the end of the Cold War, there was no obvious rationale for the Atlantic Alliance’s continued existence.  Indeed, a prime advocate of NATO expansion, Zbigniew Brzezinski, an influential strategist who had served as President Jimmy Carter’s National Security Adviser, averred that NATO would either expand or face a crisis of purpose, and though he did recommend a parallel “transcontinental security structure that embraces Russia,” he certainly did not envisage eventual Russian membership in the alliance. His objective was to provide a new basis for NATO’s continuation.[69] A similar concern animated proposals for NATO’s plunge into “out-of-area” operations—that is, taking on responsibility for managing conflict beyond Europe.  No formulation better captured this motivation than the now-famous quip of Senator Richard Lugar (R—IN), who, in a speech at the State Department in 1993, remarked that that NATO, having successfully achieved its foundational purpose, namely deterring the USSR, now faced the choice of “going out of area or out of business.”[70]

Just as NATO expansion in Europe contributed to tension between Russia and the West, so did the out-of-area gambit.  Consider Yeltsin’s apoplectic reaction to NATO’s 1999 unilateral intervention in Kosovo or Putin’s ire at the 2011 Libya intervention, especially once it morphed into a mission for regime change, thus exceeding the original UN mandate of protecting civilians.  Overall, Moscow viewed NATO’s out-of-area operations as further evidence that Washington saw the alliance as a vehicle for consolidating the unipolar moment.  This was unacceptable to Russia’s leaders.

Moreover, they continue to fear that NATO expansion preserves American global primacy.  It would be wrong to dismiss this apprehension as mere paranoia.  European dependence on the United States for security provides Washington with enormous influence—an advantage it can utilize in various realms.  The United States is the leader of the West because it possesses vastly more military power than its alliance partners.  True, Washington is wont to complain—and in my view with justification—about its NATO partners’ failure to do their fair share for the common defense; but the imbalance in defense spending also serves as a stick with which the U.S. can beat its allies periodically while simultaneously benefiting from their dependence on it. Beyond that, NATO’s continued existence provides the United States with an array of military assets—such as ports and airfields—that sustain its capacity to project its power far and wide and, beyond that, to intervene with the gloss of multilateralism and democratic norms. That doesn’t mean that such interventions do not encounter international criticism—they have and will—but it does mean that they do not provoke the international backlash that naked, might-makes-right unilateralism would. That many of these interventions have a mixed track record and have led to some of the forever wars of which much of the American public has gotten weary, while true, is a matter for discussion, but on another occasion.[71]




Was NATO expansion good for security?  The security of whom?  As Arnold Wolfers taught us, “security” is a referent object.[72] It may not mean the same thing to all actors.  Indeed, NATO members today have decidedly different views regarding not only what it means for their nations to be ‘secure,’ but also the nature of the threats and challenges facing the Atlantic Alliance and the role it should play in confronting them.

According to the pro-expansionists of the 1990s and early 2000s, enlarging NATO would make all of Europe more secure.  It would make Eastern and Central Europe more secure by bringing the countries there under the collective defense umbrella, and the 16 members in ‘old’ NATO more secure by removing the danger that conflicts in these regions would spill over into their territories.

At first glance, the evidence appears strongest for NATO’s newest members.  The conventional wisdom and some scholarly accounts hold that enlarging the Alliance improved the security of Eastern and Central European countries.[73] Yet even in the case of the new members, there are reasons for doubting such claims.  While we cannot run a natural experiment and ascertain the counterfactual, i.e., whether, absent NATO expansion, the security situations of these countries would be better or worse, the contemporary situation does offer some useful clues.  Looking at Eastern Europe today, it seems clear that NATO membership has not allayed the newest allies’ security concerns, despite the constant efforts of other allies to do so.

Following Russia’s annexation of Crimea in 2014, NATO undertook the largest reinforcement of collective defense since the Cold War.  Many of these measures, such as the “enhanced Forward Presence,” were exclusively directed at strengthening deterrence and defense along the Alliance’s eastern flank, and intended to assure newer NATO members of their fellow allies’ commitment to their security. In addition to participating in NATO’s collective efforts, U.S. European Command established a separate military operation of its own, Atlantic Resolve, designed to further demonstrate Washington’s commitment to the security of Eastern Europe.  Yet judging by the statements and additional security requests emanating from the capitals of these countries of late one would hardly conclude that they feel more secure.

Earlier this summer, following President Donald Trump’s sudden announcement that he was ordering the Pentagon to remove 9,500 troops from Germany, several NATO members began actively lobbying for U.S. military personnel to be transferred to their countries.[74]  While we lack a window into the behind-the-scenes negotiations that took place, only three allies to date have publicly campaigned to host the U.S. forces slated to be removed from Germany: Poland, Latvia, and Lithuania. Although Secretary of Defense Mark Esper’s July 2020 briefing indicated that some U.S. headquarters personnel who are currently deployed to Germany would be transferred to Belgium and Italy, neither country publicly lobbied for these changes, possibly due to their leaders’ understanding that being seen actively working to derive benefit at the expense of another ally risks jeopardizing Alliance cohesion.

In discussing the planned drawdown of U.S. forces in Germany, Esper further suggested it was likely that some of these forces would eventually be transferred to the Baltics and declared, “We are following in many ways the boundary east, where our newest allies are.”[75]  Even before this latest announcement, the Defense Department had been working on plans to move an additional 1,000 U.S. troops to Poland. Although the precise configuration of the Pentagon’s changes to the U.S. force posture in Europe remains unclear, one thing seems certain: the eastern most members of the Alliance will continue to ask for additional security reinforcements.

The reason for this comes down to basic geography.  The proximity of many of NATO’s newest members to Russia ensures that these countries will continue to experience insecurity for the foreseeable future.  Consequently, their appetite for additional NATO (and especially U.S.) military contributions is likely to be infinite.  No amount of troop contributions will satiate these countries’ security concerns for the simple reason that, while they may have joined what is frequently heralded as the most successful military alliance in history, their national histories and geography dictate they will always fear Russia and feel insecure.

While the current situation on the Alliance’s eastern flank in some respects resembles the experience of Western Germany during the Cold War, there are two important differences.  First, Russia is not the Soviet Union and the Warsaw Pact is no more.  Second, while differing perceptions of the Soviet Union existed during the Cold War, all 16 members agreed that Moscow constituted the primary threat.  All of NATO’s activities and energies, in other words, were oriented toward a single task during the Cold War, that of countering the Soviet adversary.  This is no longer the case.  Today’s NATO is increasingly divided over the nature of the Russian threat and how the Alliance can best counter it.  While newer members continue to lobby for more security investments, older allies like Turkey are busily purchasing weapons from the Russians, and France is openly exploring rapprochement with Moscow.  Thus, unlike during the Cold War, the allies themselves no longer agree on which threats and challenges the Alliance should focus on.  Rather than confronting this unpleasant reality and launch a new strategic review to replace the outdated 2010 Strategic Concept, NATO leaders, who are fearful that such an exercise would only widen existing cracks, have instead sought to gloss over the growing strategic rift within the Alliance by seeking to please old and new members alike by tackling their myriad security concerns.

By rapidly expanding eastward in the late 1990s and early 2000s, NATO all but ensured a strategic rift would develop between older and newer members.  One consequence of enlargement therefore has been the weakening of the cohesion of the Alliance.  Every call by newer members for the Alliance ‘to do more’ to protect them is now met by the rejoinder that NATO cannot simply mean security for some allies; it must mean security for all allies.  Seeking to satisfy the security concerns of all 30 of its members —many of whom perceive distinct threats to their national security—Alliance leaders struck a Faustian bargain.  In an attempt to thread this impossible needle, NATO leaders adopted an ever-expanding list of security tasks onto their agenda, ranging from traditional security threats to non-traditional ones like stemming illegal migration. NATO’s fragmentation and strategic malaise today are thus one legacy of expansion.



[1] James Goldgeier and Joshua R. Itzkowitz Shifrinson, “Evaluating NATO Enlargement: Scholarly Debates, Policy Debates, and Roads Not Taken,” International Politics 57:3 (2020): 291-321.  This piece frames the special issue, Legacies of NATO Enlargement: International Relations, Domestic Politics, and Alliance Management.

[2] Craig Turp-Balazs, “NATO chief tells Georgian PM to ‘prepare for membership’,” Emerging Europe, 29 September 2020; https://emerging-europe.com/news/nato-chief-tells-georgian-pm-to-prepare-for-membership/.

[3] See for an elaborate discussion on these benefits of enlargement. Alexander Lanoszka, “Thank Goodness for  NATO Enlargement,” International Politics 57 (2020): 451–470. See also Joshua R. Shifrinson, “NATO Enlargement and US Foreign Policy: The Origins, Durability, and Impact of an Idea,” International Politics 57:3 (2020): 358–359.

[4] George H.W. Bush, “A Europe Whole and Free” (Mainz, May 1989), https://usa.usembassy.de/etexts/ga6-890531.htm.  In interviews with the author, officials repeatedly characterized the process as one of consolidation. Paul van Hooft, “Land Rush: American Grand Strategy, NATO Enlargement, and European Fragmentation,” International Politics 57:3 (2020): 530–553.

[5] The shift began as early as the 1990 NATO summit in London, but culminated in a new strategic concept by the end of the decade.  NATO, “The Alliance’s Strategic Concept Approved by the Heads of State and Government Participating in the Meeting of the North Atlantic Council in Washington D.C.,” 24 April 1999, http://www.nato.int/cps/en/natohq/official_texts_27433.htm.

[6] Van Hooft, “Land Rush,” 545–547; Sara Bjerg Moller, “Twenty Years after: Assessing the Consequences of Enlargement for the NATO Military Alliance,” International Politics 57:3 (2020): 515–516; Theo Farrell and Sten Rynning, “NATO’s Transformation Gaps: Transatlantic Differences and the War in Afghanistan,” The Journal of Strategic Studies 33:5 (2010): 673–674; Kaija Schilde, “European Military Capabilities: Enablers and Constraints on EU Power?,” JCMS: Journal of Common Market Studies 55:1 (2017): 37–353.

[7] Van Hooft, “Land Rush,” 539–540; Joshua R. Itzkowitz Shifrinson, “Eastbound and down: The United States, NATO Enlargement, and Suppressing the Soviet and Western European Alternatives, 1990–1992,” Journal of Strategic Studies, online 1 April 2020; Timothy Andrews Sayle, Enduring Alliance: A History of NATO and the Postwar Global Order (Ithaca: Cornell University Press, 2019): 234–35; Kori Schake, “NATO after the Cold War, 1991–1995: Institutional Competition and the Collapse of the French Alternative,” Contemporary European History 7:3 (1998): 379–407.

[8] The 2002-2003 transatlantic clash over the Iraq War. Van Hooft, “Land Rush,” 543.

[9] Van Hooft, 539–40; see also Shifrinson, “NATO Enlargement and US Foreign Policy,” 353–54.

[10] Van Hooft, “Land Rush,” 533–534.

[11] Van Hooft, “Land Rush,” 542.

[12] Department of Defense, National Defense Strategy of the United States of America (2018); https://dod.defense.gov/Portals/1/Documents/pubs/2018-National-Defense-Strategy-Summary.pdf.

[13] Department of Defense, National Defense Strategy.  The Indo-Pacific is “the single most consequential region for America’s future.” Department of Defense, Indo-Pacific Strategy Report Preparedness, Partnerships, and Promoting a Networked Region (June 2019); https://media.defense.gov/2019/Jul/01/2002152311/-1/-1/1/DEPARTMENT-OF-DEFENSE-INDO-PACIFIC-STRATEGY-REPORT-2019.PDF.

[14] See recent work on the possibility for opportunism by either Russia or China in case of escalation in either Europe or Asia. Hal Brands and Evan Braden Montgomery, “One War Is Not Enough: Strategy and Force Planning for Great Power Competition,” Texas National Security Review 2:3 (2020); Hal Brands and Evan Braden Montgomery, “Opportunistic Aggression in the Twenty-First Century,” Survival 62:4 (2020): 157–182.

[15] Office of the Under Secretary of Defense, Nuclear Posture Review (February 2018); https://dod.defense.gov/News/SpecialReports/2018NuclearPostureReview.aspx.

[16] Van Hooft, “Land Rush,” 543.

[17] Kimberly Marten, “NATO Enlargement: Evaluating Its Consequences in Russia,” International Politics 57:3 (2020): 1–26.

[18] Lanoszka, “Thank Goodness for NATO Enlargement,” 464–465.

[19] John J. Mearsheimer and Stephen M. Walt, “The Case for Offshore Balancing: A Superior US Grand Strategy,” Foreign Affairs 95:4 (2016): 70; Barry R. Posen, Restraint: A New Foundation for US Grand Strategy (Ithaca: Cornell University Press, 2014): 33, 35, 44.

[20] See an early critique of this problem. Joseph Lepgold, “NATO’s Post-Cold War Collective Action Problem,” International Security 23:1 (1998): 78-106.

[21] Susanne Nies, “L'élargissement de l'OTAN : quelles répercussions sur les nouveaux membres et sur la structure de l'Alliance ?”, Revue Internationale et stratégique 3:59 (2005): 53.

[22] John L. Gaddis, “History, Grand Strategy, and NATO Enlargement,” Survival 40:1 (1998): 145-151; George F. Kennan, “A Fateful Error,” The New York Times, 5 February 1997.

[23] Sara Bjerg Moeller, Twenty Years After: Assessing the Consequences of Enlargement for the Military Alliance,” International Politics 57:3 (2020): 509-529.

[24] Andrew A. Michta, “NATO Enlargement Post-1989. Successful Adaptation or Decline,” Contemporary European History 18:3 (August 2009): 364.

[25] Robert Kuttner, “Was Putin Inevitable?” American Prospect, 30 January 2020; https://prospect.org/world/was-putin-inevitable/.

[26] Kimberly Marten, “Reconsidering NATO Expansion: A Counterfactual Analysis of Russia and the West in the 1990s,” European Journal of International Security 3:2 (November 2017): 137. 

[27] Joshua Shifrinson, “Time to Consolidate NATO?” The Washington Quarterly 30:1 (2019): 119.

[28] Quotes from John J. Mearsheimer, “Bound to Fail: The Rise and Fall of the Liberal International Order,” International Security 43:4 (2019): 23, 33.

[29] Stephen M. Walt, The Hell of Good Intentions: America’s Foreign Policy Elite and the Decline of US Primacy (New York: Farrar, Straus, and Giroux, 2018): 32.

[30] Paul van Hooft, “Land Rush: American Grand Strategy, NATO Enlargement, and European Fragmentation,” International Politics 57:3 (2020): 530–553.

[31] “Lavrov: EU, NATO wrong to force ‘West or Russia’ on the Balkans,” Euractiv, 19 February 2018; https://www.euractiv.com/section/enlargement/news/lavrov-eu-nato-wrong-to-force-west-or-russia-on-the-balkans/.

[32] See Alexander Lanoszka, “Thank Goodness for NATO Enlargement,” International Politics 57:3 (2020): 451–570.

[33] Quotes from John J. Mearsheimer, “Back to the Future: Instability in Europe after the Cold War,” International Security 15:1 (1990): 30-33.

[34] Stephen Van Evera, “Hypotheses on Nationalism and War,” International Security 18:4 (1994): 9

[35] Gati discussed in James J. Goldgeier, Not Whether but When: The U.S. Decision to Enlarge NATO (Washington, D.C.: Brookings Institution Press, 1999): 31; and Ronald D. Asmus, Richard L. Kugler, and F. Stephen Larrabee.  “NATO Expansion: The Next Steps,” Survival 37:1 (1995): 7–33.

[36] Mearsheimer’s offensive realism should predict that Russia should strive for regional hegemony.  See idem, The Tragedy of Great Power Politics (New York: W.W. Norton, 2001).  Another critic of NATO enlargement—Barry Posen—anticipated that Ukraine and Russia would conflict and so advocated for Ukraine to have nuclear weapons.  Barry R. Posen, “The Security Dilemma and Ethnic Conflict,” Survival 35:1 (1993): 27–47.

[37] Michael E. Brown, “The Flawed Logic of NATO Expansion,” Survival 37:1 (1995): 35–36.

[38] For more on entrapment, see Alexander Lanoszka, “Tangled Up in Rose?  Theories of Alliance Entrapment and the 2008 Russo-Georgian War,” Contemporary Security Policy 39:2 (2018): 234–257.

[39] Andrei Kortunov, “NATO Enlargement and Russia: In Search of an Adequate Responses,” in David G. Haglund, ed., Will NATO Go East?  The Debate over Enlarging the Atlantic Alliance, ed. (Kingston, ON: Queen’s University Centre for International Relations, 1996): 71-82; and Timothy J. Colton and Henry E. Hale, “The Putin Vote: Presidential Electorates in a Hybrid Regime,” Slavic Review 68:3 (2009): 473–503.

[40] Anton La Guardia, “NATO is no Problem in Baltics, Putin tells the West,” Telegraph, 3 April 2004, retrieved from https://www.telegraph.co.uk/news/worldnews/europe/russia/1458449/Nato-is-no-problem-in-Baltics-Putin-tells-the-West.html.

[41] See Kimberly Zisk Marten, “Reconsidering NATO Expansion: A Counterfactual Analysis of Russia and the West in the 1990s,” European Journal of International Security 3:2 (2018): 157–159.

[42] Alexander Lanoszka and Michael A. Hunzeker, Conventional Deterrence and Landpower in Northeastern Europe (Carlisle: U.S. Army War College).

[43] Alberto Priego, “NATO Enlargement: A Security Dilemma for Russia?” in Roger E. Kanet, ed., Routledge Handbook of Russian Security (London: Routledge, 2019), 257-265.

[44] Rajan Menon and William Ruger, “NATO Enlargement and US Grand Strategy: A Net Assessment,” International Politics 57:3 (June 2020): 3713-3740.

[45] Samuel Charap and Mikhail Troitskiy, “Russia, the West, and the Integration Dilemma,” Survival 55:6 (December 2013-January 2014): 49-62.

[46] Simon Duke and Carmen Gebhard, “The EU and NATO’s Dilemmas with Russia and the Prospects for Deconfliction,” European Security 26:3 (2017): 379-397.

[47] Andrew Kydd, “Trust Building, Trust Breaking: The Dilemma of NATO Enlargement,” International Organization 55:4 (Autumn 2001): 801-828.

[48] Andrey A. Sushentsov and William C. Wohlforth, “The Tragedy of US-Russian Relations: NATO Centrality and the Revisionists’ Spiral,” International Politics 57:3 (June 2020): 427-450.

[49] Kimberly Marten, “Reconsidering NATO Expansion: A Counterfactual Analysis of Russia and the West in the 1990s,” European Journal of International Security 3:2 (June 2018): 135-161; Marten, “NATO Enlargement: Evaluating Its Consequences in Russia,” International Politics 57:3 (June 2020): 401-26.

[50] Shiping Tang, “The Security Dilemma: A Conceptual Analysis,” Security Studies 18:3 (2009): 587-623.

[51] Charles L. Glaser, “The Security Dilemma Revisited,” World Politics 50 (Oct. 1997): 171-201, quote from p. 181.

[52] Robert Jervis, “Cooperation under the Security Dilemma,” World Politics 30:2 (Jan. 1978): 167-214.

[53] Stephen M. Walt, “Alliance Formation and the Balance of World Power,” International Security 9:4 (Spring 1985): 3-43.

[54] Jeffrey Simon, Poland and NATO: A Study in Civil-Military Relations (Lantham: Rowman and Littlefield, 2004); Laura Chappell, “Strategic Posture Review: Poland,” World Politics Review, 25 August 2009, https://www.worldpoliticsreview.com/articles/5061/strategic-posture-review-poland.

[55] Tomasz Paszewski, “Can Poland Defend Itself?” Survival 58:2 (2016): 117-134.

[56] David A. Shlapak and Michael Johnson, “Reinforcing Deterrence on NATO's Eastern Flank: Wargaming the Defense of the Baltics,” RAND Research Report RR-1253-A, 2016, https://www.rand.org/content/dam/rand/pubs/research_reports/RR1200/RR1253/RAND_RR1253.pdf

[57] Stephen Sestanovich, “Could It Have Been Otherwise?” American Interest 10:5 (May/June 2015): 7-15.

[58] Email to the author from former NATO Deputy Secretary General Alexander R. Vershbow, 10 April 2017.

[59] Clint Reach, Vikram Kilambi, and Mark Cozad, Russian Assessments and Applications of the Correlation of Forces and Means (Santa Monica: RAND, 2020).

[60] Dorinel Moldovan, Plamen Pantev, and Matthew Rhodes, Joint Task Force East and Shared Military Basing in Romania and Bulgaria, Occasional Paper 21 (Garmisch-Partenkirchen, Germany: George C. Marshall European Center for Security Studies, 2009).

[61] Vladimir Putin, “Speech and the Following Discussion at the Munich Conference on Security Policy,” 10 February 2007, http://en.kremlin.ru/events/president/transcripts/24034.

[62] “Russia Gains Military Base In Abkhazia,” RFE/RL, 17 February 2010, https://www.rferl.org/a/Russia_Gains_Military_Base_In_Abkhazia/1960545.html.

[63] Michael Petersen, “The Naval Power Shift in the Black Sea,” War on the Rocks, 9 January 2019, https://warontherocks.com/2019/01/the-naval-power-shift-in-the-black-sea/

[64] William J. Burns, The Back Channel: A Memoir of American Diplomacy and the Case for Its Renewal (New York: Random House, 2019), 318.

[65] Celeste A. Wallander, “Russia’s Strategic Priorities,” Arms Control Today 32:1 (2002): 4-6.

[66] For a recent argument along these lines, see, for example, Michael McFaul, “Russia As It Is: A Grand Strategy for Confronting Putin,” Foreign Affairs 9:4 (July/August 2018): 82-91.

[67] “Bucharest Summit Declaration,” 3 April 2008, https://www.nato.int/cps/en/natolive/official_texts_8443.htm.

[68] Mikhail Gorbachev, address to the Council of Europe, Strasbourg, France, 6 July 1989, http://chnm.gmu.edu/1989/archive/files/gorbachev-speech-7-6-89_e3ccb87237.pdf.

[69] Zbigniew Brzezinski, “NATO—Expand or Die?” New York Times, 28 December 1994, https://www.nytimes.com/1994/12/28/opinion/nato-expand-or-die.html.

[70] Senator Richard Lugar, “NATO: Out of Area or Out of Business,” 2 August 1993, Media Release, Richard Lugar Papers, Indiana University (Bloomington), https://collections.libraries.indiana.edu/lugar/items/show/342.

[71] This essay is a partial summary of Rajan Menon and William Ruger, “NATO Expansion and US Grand Strategy: A Net Assessment,” International Politics 57:3 (2020): 371-400.

[72] Arnold Wolfers, “‘National Security’ As an Ambiguous Symbol,” Political Science Quarterly 67:4 (December 1952): 481-502.

[73] See, for example, Alexander Lanoszka’s essay in this roundtable.

[74] “Donald Trump orders 9,500 troops to leave Germany,” Reuters, 5 June 2020.

[75] “U.S. To Move Troops From Germany, In Shift That Esper Says Will Strengthen NATO Against Russia,” RFE/RL, 29 July 2020.