Introduction
The seventy-fifth anniversary of the North Atlantic Treaty Organization (NATO) in 2024 inspired several exceptional new histories of the alliance at a time of growing crisis in relations between the United States and its European allies. Collectively, these works point to an important paradox at the heart of the alliance’s history.Footnote 1 Has NATO persisted in its raison d’être for over seventy-five years in spite or because of the enduring challenges that have defined it for decades? The four monographs reviewed here demonstrate that these two lines of argument are almost impossible to disentangle, and that in fact, NATO is defined as much by its most persistent challenges as it is by its resolute principles and select membership. In other words, the idea of collective defence embedded in the North Atlantic Treaty of 1949 has proven to be as resilient as the challenges that the treaty was originally intended to resolve. For the purpose of this review, these most persistent challenges include stability on the European continent and varying threats to this stability posed by the Soviet Union up until 1991 and the Russian Federation after 1991, as well as the occasionally difficult leadership role of the United States within the alliance. This review will focus in particular on the contribution of each volume to the ongoing debate on NATO expansion in the aftermath of the Cold War and on the questions this raised for the paradox at the heart of the alliance’s raison d’être.
All four works under review here offer historical background on current-day policy debates pertaining to alliance politics, to shifting spheres of influence in Europe and to the threat of armed conflict. They may not necessarily shake up the field itself, but they clearly demonstrate that the precise nature of the relationship between NATO and the transatlantic security architecture of the twentieth and twenty-first centuries remains as important as it remains contested. In 2025, Sten Rynning, the director of the Danish Institute for Advanced Study of the University of Southern Denmark, published a comprehensive study, entitled NATO from Cold War to Ukraine: A History of the World’s Most Powerful Alliance. Around the same time, journalist and former British Army officer Peter Apps released his own masterfully detailed account of the alliance’s trajectory, titled Deterring Armageddon: A Biography of NATO. Both volumes trace the seventy-five-year history of NATO in a clear and accessible way that speaks to both a specialist and a non-specialist audience. Both volumes take stock of the current state of the field as a whole and reveal the ongoing conceptual tensions and competing imperatives that the alliance continues to grapple with while facing increasingly intense public scrutiny on both sides of the Atlantic. In contrast, Stephan Kieninger’s 2025 Securing Peace in Europe: Strobe Talbott, NATO and Russia after the Cold War makes a clear scholarly intervention in the field, focusing specifically on the uneasy leadership role of the United States within NATO immediately after the end of the Cold War. His research rebuts widely debated present-day contentions that the West exploited Russia’s weakness after the Cold War and that this ultimately contributed to the Russian invasion of Ukraine in 2022. The final volume under review specifically addresses the resurgence of armed conflict in Europe despite continued American leadership within the alliance and despite the alliance’s persistent presence in large parts of the continent over the course of seventy-five years. Military adviser Franz-Stefan Gady’s 2024 Die Rückkehr des Krieges: Warum wir wieder lernen müssen, mit Krieg umzugehen (The Return of War: Why We Must Learn to Deal with War Again) argues that war on the European continent is becoming increasingly likely, yet that Europeans are ill prepared for its resurgence. It is a wakeup call for anyone invested in the safety and stability of the Transatlantic region.
Gady’s account ties in neatly with that of Peter Apps, who begins his narrative on NATO’s role in transatlantic relations with the humbling premise that the alliance is an inherently imperfect and internally divided institution, whose decision-making procedure by consensus can paradoxically prevent the most fundamental issues from being resolved at all.Footnote 2 In Apps’s assessment, NATO is ultimately a flawed protagonist in a multi-decade struggle to stop a global war from breaking out in Europe once more, and as Gady warns, that struggle is far from finished.Footnote 3 Sten Rynning cautions that in order to succeed in this struggle, NATO should first and foremost address the recurrent issue of trust among its members. American policymakers have frequently and openly doubted whether their European allies are capable of defending themselves, while European policymakers have often worried that their American allies might not come to their defence in the event of armed aggression despite their commitment to the North Atlantic Treaty. The current Trump administration deliberately fans the flames of both these persistent stereotypes, and to date, the alliance has not managed to comprehensively resolve these differences. Both Rynning and Apps recommend that in order to address these issues, NATO allies should curtail their geopolitical aspirations, focus on building shared Western values and refrain from assuming that American leadership can resolve the alliance’s internal politics.Footnote 4 As such, although they are both works of history, they consciously contribute to current debates on NATO’s internal politics.
Focusing more explicitly on the external politics of the alliance, Stephan Kieninger’s monograph explores the transition from NATO’s relationship with the Soviet Union to its relationship with the Russian Federation after 1991. As such, Kieninger explicitly addresses a core question within the field of contemporary European security, namely the effect of post–Cold War NATO enlargement on East–West relations: to what extent did NATO enlargement deteriorate relations between NATO and the Russian Federation in the aftermath of the Cold War? Kieninger contends that the Clinton administration and its NATO allies made repeated attempts to turn their relations with Russia into a constructive partnership during this period.Footnote 5 Russian policymakers, however, genuinely resented the emergence of the post–Cold War security system in Europe.Footnote 6 In engaging with this ongoing debate in the literature, Kieninger focuses primarily on the role of Strobe Talbott in designing the post–Cold War European security order. Talbott served as Special Advisor to Secretary of State Warren Christopher on the New Independent States from 1993 to 1994 and as Deputy Secretary of State from 1994 to 2001.
Kieninger convincingly argues that Talbott was an important historical personality for understanding NATO’s history. He thereby revises established accounts that primarily focus on cabinet-level decision makers and makes a novel contribution towards our understanding day-to-day diplomatic decision-making.Footnote 7 In his advisory role on formerly Soviet states, he grasped both the need for a fundamentally new European security architecture and the diverging views within the Clinton administration, its NATO European allies and their former Warsaw Pact adversaries on what this architecture should look like. Kieninger also shows compellingly that Talbott’s views on the role and composition of NATO evolved over time, although he could arguably have done more to explain whether or not evolving views were an asset or a detriment to effective policy-making in the long term. On the whole, Kieninger decisively rejects claims that under Talbott’s stewardship, NATO enlargement proceeded too quickly or ‘without attention to Russian concerns’ between 1997 and 2004.Footnote 8 That is a contentious but not isolated claim within the literature on NATO enlargement and one this review will explore in some detail. In the meantime, suffice it to say that his line of argument justifies Kieninger’s choice title, namely that of Securing Peace in Europe during the 1990s.
The title of Franz-Stefan Gady’s recent monograph on Europe’s present predicament implies the exact opposite to securing peace. Die Rückkehr des Krieges quite literally means The Return of War. In his recent book, Gady acknowledges sustained efforts on behalf of the alliance and of the United States in particular, to secure peace in Europe. Yet he asserts that against the backdrop of the Russian war in Ukraine and the present-day uncertainty surrounding the continued commitment of the United States to the alliance, ‘We have to face the phenomenon of war again’.Footnote 9 Gady argues that most wars result from misjudgements about political and military leadership. It is almost impossible to predict how future wars will be fought and how they will end.Footnote 10 Yet he contends that in the current geopolitical climate, miscalculations are more likely to occur for three reasons. First, European policymakers have become largely unfamiliar with the root causes of war. Second, complex military technologies lead some to believe that war can be fought with precision. Lastly, the relative consensus within the United States on America’s role in the global order has diminished in recent years.Footnote 11 Through these arguments, Gady makes a compelling case for including a European perspective in current debates on the resurgence of armed conflict.
The Persistence of NATO
Against the backdrop of these debates, it is worth dwelling on the origins and purpose of the transatlantic alliance, which both Peter Apps and Sten Rynning do extensively in their respective contributions. At the outset of his monograph, Rynning argues that the fundamental purpose of NATO has always been to secure peace for its community. This vision persists, but at times, it has been challenging for the allies to uphold.Footnote 12 During the Second World War, the term ‘allies’ referred to the United States, the United Kingdom, the Soviet Union and others in their fight against the Axis powers, which included Germany, Italy and Japan. Yet, as is the case for most military alliances, theirs did not outlast the war. By the mid-1940s, the European continent was worn down by years of armed conflict and decision makers on both sides of the Atlantic anticipated electoral victories for communist parties against the backdrop of severe economic downturn.Footnote 13 While most European governments still feared the resurgence of Germany, Peter Apps writes that American policymakers expected the Soviet Union to underestimate the commitment of the United States to the defence of Europe and attempt to expand its influence westwards.Footnote 14 Assessing the strength of the US’s commitment was to become a persistent challenge for the alliance.
By April of 1948, the National Security Council (NSC) of the United States deliberated various proposals for not just the defence of Europe but also a global network of alliances.Footnote 15 Against the backdrop of a communist coup in Czechoslovakia and the Soviet blockade of Berlin in 1948, American policymakers began to favour the idea of collective defence for Western Europe and the wider Atlantic area. This, Rynning contends, was a uniquely American vision, as opposed to a European one.Footnote 16 European efforts to form collective defence arrangements had thus far produced a limited degree of collectivity among them. The Dunkirk Treaty of 1947 was a bilateral defence treaty against Germany between the United Kingdom and France. The Benelux states joined this arrangement in the form of the Brussels Treaty of 1948. To maintain an allied command structure in peacetime, as the North Atlantic Treaty of 1949 proposed to do, was a novel idea, something that has already been addressed at length in previous scholarship.Footnote 17
The North Atlantic Treaty of 1949 was ambitious in its aims to strengthen free institutions and to promote political stability.Footnote 18 It commits each ally to contribute to the collective defence effort and provides a mechanism for joint consultation in the event of a perceived threat by an alliance member.Footnote 19 Most notably, article five of the treaty interprets an armed attack on one member to be an attack against all.Footnote 20 This is the essence of NATO’s deterrence mechanism. What is remarkable about it is that to date, this mechanism persists despite only having been invoked once in response to the terrorist attacks of 9/11 in 2001 and despite ongoing internal disagreements among alliance members over their respective responsibilities in the event of an act of armed aggression. Both Apps and Rynning emphasise the paradox inherent in this set of circumstances and stress that it is unique to NATO as a military alliance.
What is more, they both explain that only in response to the outbreak of armed conflict did NATO develop its present-day bureaucratic structures, suggesting that the logic of collective defence of the North Atlantic Treaty did not itself appear sufficient to coordinate a military response among allies.Footnote 21 Following the outbreak of the Korean War in 1950, the alliance established an elaborate command structure under the leadership of a Military Committee, created the post of the secretary general and the infrastructure of a permanent secretariat in Paris.Footnote 22 Both Rynning and Apps document these developments in detail as part of their larger institutional histories of the alliance, yet they could have done more to address the interplay between the growing structures and membership of the alliance with those of its Cold War adversary. In 1952, Greece and Turkey joined the alliance, and in 1955, its members admitted West Germany.Footnote 23 That same year, the Soviet Union launched a rival military alliance, which included Romania, Poland, Hungary, Czechoslovakia, Bulgaria, Albania and East Germany. The Warsaw Pact features surprisingly scarcely in Rynning’s, App’s and Kieninger’s accounts. They could all have benefited from engaging more pro-actively with some of the relatively recent scholarship into the evolution of the Warsaw Pact alongside NATO over the course of the Cold War, including Mark Kramer’s, Matěj Bílý’s and Laurien Crump’s recent work, who show that the Warsaw Pact was anything but the unitary actor it was long assumed to be.Footnote 24
Both NATO and the Warsaw Pact faced serious internal crises almost immediately after their inception. Paradoxically, these were primarily internal crises among their own members, which appears to suggest that the logic of collective defence also created problems of its own for both alliance systems. In 1956, Hungary attempted to leave the Warsaw Pact, prompting a brutal Soviet military reprisal. That same year, the United Kingdom and France launched an armed offensive against Egypt together with Israel in response to Egyptian President Gamal Abdel Nasser’s decision to nationalise the Suez Canal. According to Peter Apps, the alliance had never experienced such a highly public disagreement among its members before, as the United States under President Eisenhower threatened to withdraw financial support from the International Monetary Fund for the United Kingdom.Footnote 25 Here, Apps could have explained in greater depth how well the alliance was set up to deal with internal crises, seeing as the alliance soon suffered another serious setback from one of its own members when the French government withdrew from its military command structure under President Charles de Gaulle in 1966. De Gaulle argued that since its inception in 1949, NATO had evolved into an ‘American protectorate’ and expelled US and NATO forces from French soil, forcing the alliance to move its headquarters to Mons in Belgium in 1967. Moreover, in 1974, both Greece and Turkey revoked their direct military involvement in the alliance, following the Turkish invasion of Cyprus. Did the alliance learn from these setbacks, and has it become more resilient as a result? After all, NATO’s raison d’être persisted despite these setbacks, and unlike the Warsaw Pact, the alliance outlasted the end of the Cold War and the collapse of the Soviet Union in 1991. How did NATO adapt differently to internal crises compared to the Warsaw Pact, and is there more to be learned from comparing the responses of the two alliance systems to internal crises? A more in-depth comparison between the two alliance systems would arguably have further enhanced both Apps’s and Rynning’s respective narratives.
These questions remain subject to debate and further research. On the whole, it can be said that the internal decision-making procedures and the inner workings of NATO at various stages of its seventy-five-year history are better understood than those of the Warsaw Pact for reasons primarily related to archival access. The decision to deploy American nuclear missiles to Europe in 1957, for instance, undoubtedly reinforced the deterrence effect of article five. On this subject, Rynning traces the establishment of NATO’s Nuclear Planning Group in 1961, the transition from the doctrine of massive retaliation to flexible response within NATO’s Military Committee between 1963 and 1967, as well as the alliance’s adoption of the so-called Harmel Report in 1967.Footnote 26 According to the report, initiated by Belgian Foreign Minister Pierre Harmel, the alliance was to adopt the dual function of military deterrence and political détente, with the purpose of reducing tensions between the two rival alliance systems. Here, both Rynning and Apps could have drawn slightly more on Susan Colbourn’s work, which suggests that the Harmel Report paved the way for the alliance’s persistence after the end of the Cold War, when allies struggled to adapt their old institutions to the political challenges of the post–Cold War era.Footnote 27 Both authors reaffirm the widespread assumption that the Harmel Report contributed to the conclusion of several far-reaching arms control agreements over the course of the 1970s and the 1980s, including two rounds of the Strategic Arms Limitation Talks (SALT) in 1972 and 1974 respectively, as well as the Intermediate-Range Nuclear Forces Treaty of 1987. They also assert, as others have before them, that neither alliance was prepared for the unexpected implosion of East Germany, following the collapse of the Berlin Wall in November of 1989.
This unexpected development raised the question of German reunification and, with it, the question of alliance membership of a reunified Germany. Rynning contends that initially, American Secretary of State James Baker proposed to integrate a unified Germany into NATO and that Hans-Dietrich Genscher, the foreign minister of West Germany, advocated for the formulation that in return, the alliance would not expand further eastward.Footnote 28 The literature on this question continues to preoccupy historians and policymakers alike against the backdrop of the present-day Russian war in Ukraine. NATO expansion is sometimes cited as a factor leading up to the war, with some advancing the contentious claim that it provoked Russian aggression. Mary Elise Sarotte points to a meeting between Baker and Gorbachev on 9 February 1990, during which some observers claim Baker assured Gorbachev that NATO would refrain from expanding beyond its eastern Cold War border.Footnote 29 Sarotte’s research challenges the existence of a formal non-expansion promise. Michael McGwire, however, argues that it constituted part of a bargain to allow a united Germany to become part of NATO, and Joshua Shifrinson contends that the Soviet Union repeatedly received assurances against NATO expansion.Footnote 30
By contrast, Susan Colbourn points out that the prospect of NATO expansion was not unprecedented and that article ten of the North Atlantic Treaty gives any European state the option to be invited to join the alliance.Footnote 31 After Greece and Turkey joined the alliance in 1952 and West Germany joined in 1955, Spain followed in 1982. Colbourn stresses that the accession of unified Germany to the alliance expanded the alliance in territorial terms, but not in its number of members.Footnote 32 Yet James Goldgeier and Joshua Shifrinson rightfully argue that NATO’s enlargement into Central and Eastern Europe, including former territories of the Soviet Union, has been among the most pre-eminent and controversial features of post–Cold War European security and American foreign policy.Footnote 33 At the time of German reunification in October of 1990, they point out, it was not even clear as to whether ‘NATO itself would persist in the post–Cold War world given the collapse of the communist threat it was founded to counter’.Footnote 34 In January of 1991, Soviet forces suppressed peaceful protests in Lithuania and Latvia. Members of the Warsaw Pact, including Czechoslovakia, Poland and Hungary, condemned these crackdowns. In February of 1991, the Warsaw Pact announced its dissolution, and on 25 December 1991, Mikhail Gorbachev dissolved the Soviet Union itself.Footnote 35 While these developments have been investigated in detail elsewhere, they provide a succinct overview for both students and newcomers to the field.Footnote 36
The Persistence of NATO’s Challenges
At first glance, the dissolution of the Soviet Union may have appeared to be a victory for NATO. Yet Stephan Kieninger rightfully points out that, ‘After the end of the Cold War, Europe’s security was a mess’.Footnote 37 The breakup of Yugoslavia in 1991 incited multiple waves of violent ethnic conflict, and in March of 1992, the United Nations (UN) deployed one of the largest peacekeeping forces in its history to the region. In April of 1993, the UN Security Council authorised a no-fly zone, which NATO ambassadors agreed to enforce for the first time in the alliance’s history.Footnote 38 That same month, the presidents of Poland and the Czech Republic, Lech Wałęsa and Václav Havel, communicated their respective desires to join NATO to American President Bill Clinton at the opening ceremony of the Holocaust Museum in Washington, DC.Footnote 39 Kieninger documents that Wałęsa received approval for his country’s wish to join the alliance from Russian President Boris Yeltsin in August of 1993, yet Yeltsin, who had been president of Russia since December of 1991, retracted his consent in a letter to Clinton the following month.Footnote 40 There is a latent consensus within the literature that the Clinton administration did not have a unified position on the subject at this point.Footnote 41 Kieninger shows that the same was the case for their Russian counterparts as well.
Initially, for instance, the Russian Federation signalled its interest in the Clinton administration’s Partnership for Peace (PfP), an informal framework of bilateral partnership agreements between NATO and non-NATO members across the European continent launched in January of 1994. Yet in June of 1994, Russian Foreign Minister Andrei Kozyrev refused to sign the PfP’s official framework agreement at a meeting of the North Atlantic Cooperation Council in Brussels. Against the backdrop of gradually shifting spheres of influence, the Russian army deployed troops into Georgia during the summer of 1994, and according to Talbott’s assessment, it was likely that Ukraine would develop into a further theatre for renewed tensions between Russia and the transatlantic alliance. Having voted for independence from the Soviet Union in December of 1991, Ukraine agreed to dismantle its remaining stockpiles of nuclear weapons at a summit in Budapest on 5 December 1994.Footnote 42 The so-called Budapest Agreement was signed by Ukraine, the Russian Federation, the United Kingdom and the United States.Footnote 43 At the time, Kieninger argues, the United States was not prepared to issue robust security guarantees to the Ukrainian government, as this was likely to lead to similar requests from other states in the former Soviet sphere of influence. Here, it would have been fascinating to know even more on Kieninger’s interpretation as to why the Clinton administration struggled to find the country a place in the Euro–Atlantic security architecture in the long term, as successive administrations have thus far been unable to find an enduring solution.
One avenue of explanation for this is that the administration was thoroughly preoccupied with a series of rapid security developments across the region. The following week, Russian forces launched a military offensive against Chechnyan separatists in the Caucasus. NATO, moreover, was by this point engaged in the first military operation of its history. Strikingly, it did not involve the provisions of NATO’s article five but rather ongoing hostilities in Bosnia and Herzegovina. NATO involvement ultimately led to a ceasefire and to the deployment of peacekeepers in October. In November of 1995, the conflict parties gathered in Dayton, Ohio, to negotiate the terms of a settlement.
Meanwhile, by the beginning of Clinton’s second term in office in 1996, the administration sought to conclude a ‘NATO–Russia Charter’ before the alliance’s summit in Madrid in July of 1997.Footnote 44 Also referred to as the so-called Founding Act, the Charter of 27 May 1997 established a Permanent Joint Council for the purpose of NATO–Russia consultation on issues such as joint peacekeeping, counterterrorism and confidence-building measures.Footnote 45 Against the backdrop of its conclusion, NATO members subsequently met in Madrid in July of 1997 and formally invited Poland, Hungary and the Czech Republic to join the alliance. In January of 1998, the Clinton administration formally endorsed Estonian, Latvian and Lithuanian membership as well, although it did not commit to a formal timeline, as Apps notes in his work.Footnote 46
Bulgaria, Estonia, Latvia, Lithuania, Romania, Slovakia, Slovenia, Albania, Croatia, Montenegro, North Macedonia, Sweden and Finland have all since joined NATO, adding to the debate on whether NATO enlargement was to blame for the deterioration in East–West relations since the early post–Cold War period. Proponents argued it would stabilise Europe and facilitate the spread of democracy and market capitalism. Critics countered that as a military alliance, NATO was not the primary vehicle for spreading either. In this respect, it would have been fascinating for the works reviewed here to have engaged more with concurrent debates on the enlargement of the European Union (EU).Footnote 47 In addition, expanding the alliance eastward would require the existing allies to defend a host of new member states, which would first need to be integrated into the alliance, all of which risked antagonising Russia.Footnote 48 In a letter addressed to President Clinton, fifty former American legislators, policymakers and foreign policy specialists warned that NATO expansion threatened to create a new line of division across the European continent, threaten the stability of the post–Cold War order and raise the cost of the United States’s commitment to Europe.Footnote 49 Yet above all, NATO expansion shifted the spheres of influence that had hitherto marked the Cold War divide on the European continent.
Kieninger asserts that American and NATO officials were not unmindful of Russian objections to NATO expansion. Yet Goldgeier and Shifrinson have pointed out in their own work that they did not stop the enlargement process either.Footnote 50 They contend that the Clinton administration assumed Boris Yeltsin would be assuaged by delaying enlargement until after the Russian presidential elections of 1996 and cooperating with the Russian Federation in areas such as the ‘NATO–Russia Charter’. Ultimately, the debate on NATO enlargement persists, with authors such as Mary Sarotte arguing that enlargement did not cause the deterioration of US–Russian relations by itself. Rather, the way in which it was implemented limited options for twenty-first-century transatlantic relations.Footnote 51 According to Kieninger, Sarotte ‘overstates the urgency and importance of the NATO enlargement track’, which he argues was not on the agenda until 1993 and which took place only gradually over the course of the 1990s.Footnote 52 Yet Sarotte’s contention that gradual enlargement ultimately limited the alliance’s options is inherent in the process itself, even as officials such as Talbott worked tirelessly to square the circle between opening up NATO membership and establishing a durable partnership with Russia in the long term. Enlargement uprooted the entrenched spheres of influence of the Cold War. Crucially, it also created new grey areas between the spheres of influence of East and West that were neither neutral nor non-aligned, most notably in Georgia and Ukraine. This had not been the case during the Cold War bipolar division of Europe during the twentieth century.
Specifically, NATO made no serious effort to extend its membership to Georgia and Ukraine. In May of 2002, for instance, NATO foreign ministers met in Reykjavik, and in November of that year, they met in Prague to discuss the further enlargement of the alliance. They subsequently extended formal membership invitations to the Baltic states, Bulgaria, Romania, Slovakia and Slovenia.Footnote 53 These states formally joined the alliance in March of 2004. Ukrainian President Leonid Kuchma, however, was encouraged not to attend the ministerial meeting in Prague so as to avoid antagonising the Russian Federation.Footnote 54 In July of 2004, Kuchma announced his government’s decision to stop pursuing membership of both NATO and the EU. Ukrainian presidential elections were scheduled for October 2004, yet in September presidential candidate Viktor Yushchenko was poisoned. His opponent, Viktor Yanukovich, was narrowly awarded an election victory in October’s presidential run-off, causing Yushchenko’s supporters to take to the streets to force a re-run of the election, which Yushchenko ultimately won. During his presidency from 2005 to 2010, Yushchenko resumed the pursuit of NATO membership for Ukraine, yet both Georgia and Ukraine were denied formal membership invitations at the alliance’s summit in Bucharest in April of 2008, a decision whose importance Apps highlights particularly in light of subsequent developments.Footnote 55 In August of that year, South Ossetian separatists launched an armed uprising in Georgia, triggering a military response from Georgia’s armed forces, which the Russian Federation in turn cited as a justification for its incursion into South Ossetia and Abkhazia over a period of sixteen days. In February of 2014, unidentified Russian forces also occupied the Ukrainian peninsula of Crimea and Eastern Ukrainian territories in the Donbas region.
Apps contends that the fighting in Georgia, in Crimea and in eastern Ukraine that followed between 2008 and 2014 ‘reoriented NATO firmly back towards “classical deterrence”’, as had been its primary purpose during the Cold War.Footnote 56 Yet NATO’s deterrence mechanism purposely did not extend to Ukraine, and on 24 February 2022, Russia launched its widely anticipated full-scale invasion. Against most expectations, it failed to capture Kyiv, and the invasion stalled. In response, the North Atlantic Council immediately mobilised 40,000 troops across Europe, and between February and April of 2022, its members began to coordinate arms shipments and supplies to Ukraine.Footnote 57 What is more, Finland and Sweden applied for NATO membership in May. According to Peter Apps, without the alliance, ‘Few of its Eastern and Central European members would have felt so confident to support Ukraine’.Footnote 58 Yet the outcome of the war remains uncertain, and so does the prospect for peace and stability on the European continent.
NATO’s Unresolved Challenges Define the Alliance
Relations among NATO allies have become even less predictable since the inauguration of the second Trump administration in January of 2025. The power imbalance between the United States and its smaller allies has ‘always been a source of tension’, according to Apps.Footnote 59 Yet both the Russian war in Ukraine and the administration’s ostentatiously hostile attitude towards Europe suggest a striking disregard for the national interest, as Franz-Stefan Gady implies from a military perspective in Die Rückkehr des Krieges.Footnote 60 He asserts that the founding premise of an alliance such as NATO is to collectively deter armed aggression against one of its members, not from amongst its members. Yet the long-term domestic consensus on this premise can no longer be taken for granted in the United States, and Gady warns that this can have concrete consequences for the resurgence and persistence of war in Europe.Footnote 61
The main argument of Gady’s recent monograph is threefold: the return of armed conflict is becoming more likely on the European continent and is less likely to lead to decisive outcomes, and as a consequence, Europeans must learn ‘that war and military might are legitimate means to secure the national interest in many parts of the world’.Footnote 62 At present, he warns that no European state would be able to defend itself in the manner that Ukraine has managed.Footnote 63 Compared to the Ukrainian armed forces, he estimates that the German Bundeswehr would have collapsed within days under the same circumstances.Footnote 64 Unlike some, he maintains that the United States will remain Europe’s most important strategic partner.Footnote 65 Yet he strongly advocates for Germany to take a leading role within NATO to deter armed aggression against the alliance, a proposition that stands in stark contrast to what many have perceived to be the de facto purpose of the alliance since its inception.
The alliance’s first general secretary, General Hastings Ismay, allegedly suggested during the early 1950s that NATO’s true purpose was to ‘keep the Soviet Union out, the Americans in and the Germans down’.Footnote 66 Gady now appears to suggest that in order to keep the Americans ‘in’ and the Russians ‘out’, Germany should be encouraged to do the opposite – to rise ‘up’ and take the leading role within the alliance. Collectively, the four monographs under review here illustrate how NATO has evolved in strategic orientation and expanded in membership over the course of its seventy-five-year history. Its enduring challenges have evolved alongside it to an extent that they have come to define the alliance as much as its treaty obligations and values. The history of NATO remains a contentious subject of scholarship and policy-making beyond its seventy-fifth anniversary, and if Gady’s analysis proves correct, its seventy-five years of experience in the domain of European security will be one of its greatest assets during the years to come.
Acknowledgements
The author thanks the review editors of Contemporary European History for their comments.
Competing interests
The author declares none.
Financial support.
This work was supported by the Ax:son Johnson Institute for Statecraft and Diplomacy.
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