they form alliances in order to manage their disagreements as well.
Military alliances are, therefore, distinct from other types of security cooperation. Unfortunately, many datasets that aim to collect information on alliances for quantitative study often pool military alliances together with coalitions, nonaggression pacts, and ententes (Wilkins 2012: 57). These arrangements should not be conflated. Coalitions are ad hoc and usually built around a specific military campaign or mission set in wartime, even though states sometimes draw on their military alliances to build those coalitions. Nonaggression pacts involve states pledging not to attack one other; they do not contain promises to render assistance if a party to the agreement comes under attack by a third party. An entente – from the French for “understanding” – is, by dint of lacking a treaty basis, “a far less conspicuous form of association than alliance” and can be construed as an amiable form of geopolitical alignment (Kann 1976: 616). Nor are military alliances “concerts,” which stress “the preservation of peace and order through the negotiated adjustment of conflict” (Snyder 1997: 368). Concerts can involve the provision of mutual protection, but, as the archetypal example of the nineteenth-century Concert of Europe indicates, they often serve to regulate interstate relations among states that do not necessarily see each other as friends, let alone as allies (Slantchev 2005: 579).
Plan of the Book
This book is about contemporary military alliance politics. Combining theoretical rigor with a historical sensibility, it will cover the main practical problems and policy debates relating to alliance management. As indicated, Chapter 1 explores why states establish military alliances. Chapter 2 tackles the issue of entrapment, whereas Chapter 3 focuses on abandonment. Chapters 4 and 5 address alliance burden-sharing controversies and coalition war-fighting, respectively. Chapter 6 discusses alliance termination. The Conclusion recapitulates the book’s arguments and offers final thoughts on the value of military alliances and the difficulties of assuring partners moving forward. US-led alliances will dominate this book because, as Table 0.1 indicates, most military alliances as of 2021 involve the United States. It will consider non-US alliances such as China–North Korea and the Russian-led Collective Security Treaty Organization (CSTO), as well as the prospects for new alliances, including one between Russia and China. Many examples will be drawn from the historical record: Germany’s late nineteenth- and early twentieth-century alliance with Austria-Hungary, France’s interwar alliances with Central European states, the Cold War-era Warsaw Pact, North Korea’s alliance with the Soviet Union, among others.
Table 0.1: Military alliances that are active as of 2021
| Involving the United States | |
| Australia, New Zealand, United States Security (ANZUS) Treaty | NATO (29 other countries) |
| Inter-American Treaty of Reciprocal Assistance (16 other countries) | Treaty of Mutual Cooperation and Security Between the United States and Japan |
| Mutual Defense Treaty Between the United States of America and the Republic of Korea | Thai–US Defense Alliance |
| Mutual Defense Treaty Between the Republic of Philippines and the United States of America | |
| Involving China | Involving Russia |
| Sino-North Korean Mutual Aid and Cooperation Friendship Treaty | Collective Security Treaty Organization (5 other countries) |
1 Formation
Why do states establish military alliances? For a time, this question no longer appeared to have policy relevance and thus could only have inspired historical interest. The Bush administration may have overseen the incorporation of seven European countries into NATO, but it failed in its bid to put Georgia and Ukraine on a clear path toward eventual membership. Most importantly, under Bush’s leadership the United States opted to build a “coalition of the willing” to wage a military campaign against Iraq. Even the NATO mission in Afghanistan saw some countries place caveats over the use of their military forces there, much to the dismay and resentment of some of their partners. With Obama taking over the White House amid profound global economic crisis in 2009, military alliances seemed to have become too rigid and impractical as a tool.
Looser security arrangements were destined to be commonplace. Thomas Wilkins (2012: 54) averred that “formal military alliances [based] on the pre-WWI/Cold War paradigm have now ceased to represent the standard for allied security cooperation.” Bruno Tertrais (2004: 139) noted unequivocally that “permanent multinational alliances appear increasingly to belong to the past.” As he saw it, many US allies had grown wary of US leadership, while the United States itself came to view alliances as much more burdensome than before. Rajan Menon (2003: 16) went further and declared “the end of alliances,” be they bilateral or multilateral. He argued: “America will revert to a pattern it has followed for most of its history, operating in the world without fixed, long-term alliances and pursuing its cooperation with a range of partners.” Echoing this sentiment, Stephen Walt (2009: 137–8) wrote that, because of its global dominance, Washington “is likely to rely more heavily on ad hoc coalitions, flexible deployments, and bilateral arrangements that maximize its own leverage and freedom of action.” Similarly, Parag Khanna (2008: 324) observed that states now operate “in a world of alignments, not alliances.”
And yet barely a decade after these pronouncements were made, military alliances began to experience a revival. Seth Cropsey (2020) of the Hudson Institute has argued in favour of “[s]trengthening the US–Taiwan Alliance [sic]” in order to improve regional defense against an increasingly powerful China. At least one scholar argues that China is “on the verge of an alliance” with Russia (Korolev 2019). In the spring of 2020, India and Australia signed a mutual logistic support agreement that would allow each country to access the other’s military balance, signaling that they may be involved in more military exchanges and exercises in the future. Already across the Indo-Pacific region a patchwork of different security relationships has taken shape between countries that have previously avoided military cooperation, suggesting that new defense pacts may yet form with the goal of managing the rise of China and its attendant challenges (Simón et al. 2021). Though admittedly more of a case of alliance enlargement than of alliance formation, the United States added two new treaty allies to its roster, with Montenegro and North Macedonia joining NATO in 2017 and 2020, respectively. Indeed, the security challenge posed by Russia following its annexation of Crimea from Ukraine reanimated NATO. Some alliance scholars have spoken of how NATO could contribute to balancing efforts against China (Moller and Rynning 2021: 185). Whereas London and Washington may have had a “special relationship” in the twentieth century to confront threats in Europe and elsewhere, Tokyo and Washington may yet have one in the twenty-first century on the basis of their Security Treaty as the center of gravity in international affairs shifts toward the Indo-Pacific.
The standard view is that states establish military alliances for at least two, non-mutually exclusive, reasons. The first is that states wish to balance
