Military Alliances in the Twenty-First Century. Alexander Lanoszka

in alliance politics that this book explores figured in the events of that one year, 2008. Those events have reverberations that carry through to the present day. The United States sought to form new official alliance partnerships by way of enlarging NATO further, only to be rejected by some of its longstanding partners out of fear of being entrapped in disputes with Russia they did not wish to have. Amid the fallout of a terrible economic crisis, allies began to worry that the United States might loosen its commitments to them, thereby stoking fears of abandonment. Some Obama administration officials – most notably, Secretary of Defense Robert Gates – would indeed later chastise US allies for free-riding and call for more equitable burden-sharing. Part of the frustration that Gates articulated emerged from the US experience in Afghanistan, where the NATO-led mission saw not only greater US troop numbers, but European partners placing caveats that inhibited the military effectiveness of their own national forces. The wars in both Iraq and Afghanistan were examples of coalition warfare that saw the participation of some US allies and partners, but not others. Still, the geopolitical shifts produced by the 2008 financial crisis suggested that some alliances could eventually come to an end, if the United States was no longer able or willing to support them. Of course, no alliance was ever truly at risk of being revoked during the Obama administration, but how sustainable such commitments could be and whether some should be terminated became increasingly a matter of debate.

What these observations also suggest is that these issues were very much alive before Trump became president in 2016 or even 2013–14 when fears of Chinese assertiveness and Russian aggression gained salience. During Trump’s first presidential election campaign, he labeled NATO as “obsolete” and suggested that the United States would not come to the aid of those allies that had not fulfilled their defense spending commitments. He intimated that he might acquiesce to efforts by South Korea and Japan to acquire their own nuclear weapons, thereby contradicting decades-old US nuclear nonproliferation policy toward treaty allies. As president, his approach to alliance management softened little. He pointedly refused to endorse Article V of the Washington Treaty (also known as the North Atlantic Treaty) – which provides that an attack on one NATO member is an attack against all – when given the opportunity to do so. He launched trade wars with European allies and Japan, and threatened major economic sanctions while renegotiating free trade agreements with Canada and South Korea – all of which were longstanding US allies. He repeatedly lambasted NATO members for not paying their fair share. His administration had demanded extortionary amounts of money from South Korea in talks over the status and financing of US bases in that country. His desire to strike deals with Russia and North Korea unsettled allies located on their frontiers, fueling concern that a grand bargain would be made at their expense.

It would thus be tempting to conclude that, given Trump’s presidency, the end of US military alliances had seemed imminent. Perhaps that really would have been the case had he won re-election in 2020. We will never know. And yet the record of the previous decade suggests an alternative assessment: many of the seemingly intractable problems that abound in alliance management today have appeared before. It is safe to say that they will persist into the future, even if Trumpism is – possibly – in the rearview mirror. As this book will show, sometimes these problems were far more severe in the past, as in the Cold War or in previous historical epochs like the interwar period in Europe. Friction is inevitable in alliance politics, especially when adversaries pose new threats and challenges. Just as in the past decision-makers were able to confront those challenges with some success, so they look poised to do so again. Contrary to appearances, the end of most US alliance commitments is not upon us. For all the vitriolic rhetoric about free-riding allies, the United States in fact stepped up its military commitments to Europe during Trump’s presidency, with an increased presence in both Germany and Poland. Trump did not withdraw major numbers of military forces from any treaty ally, despite a late effort to rearrange US force posture in Europe (Lanoszka and Simón 2021). Under his administration, the United States acquired new treaty allies when Montenegro and North Macedonia joined NATO in 2017 and 2020, respectively.

      That said, as the events in 2008 demonstrated, changes are afoot in world politics that portend important adjustments in US security guarantees in Europe and East Asia, on the one hand, and, on the other, military partnerships that involve China, Russia, or both. These changes are not reducible to the personal character or rhetoric of any one leader, including someone like Trump, Putin, or even Xi. Rather, these changes reflect a transforming international environment characterized by the rise of China, the roguishness of Russia, and the maturation and proliferation of once cutting-edge technologies like precision strike as well as the malicious use of cyber operations and disinformation campaigns. In fact, these changes had already begun years before Trump declared his candidacy for the US presidency, and will continue to unfold into the future. After all, alliance politics is usually marked by divergent geopolitical interests, worries about the consequences of commitment-making, and, in today’s technological context, burden-sharing controversies. These issues will shape alliance politics going forward even if Trump’s successor, Joseph Biden, has consistently spoken favorably of US military alliances. The SARS-CoV-2 pandemic could accelerate these trends as countries grapple with its economic and political fallout.

The Arguments of this Book

Alliance politics will remain a persistent feature of international affairs, but, as this book argues, that is because military alliances operate in ways that are often surprising, counterintuitive, and difficult to understand. To see why, consider the following standard claims that scholars and practitioners often make regarding how alliances function, or should function, from when these arrangements are first negotiated to when they meet their eventual demise. In outlining, in the discussion below, what those pieces of conventional wisdom are and why they are problematic, I offer a preview of the argument that each chapter in this book advances.

Conventional wisdom #1: States form alliances to balance power and/or to gain influence over other states

      Many observers agree that states form military alliances in order to aggregate power in the face of a security challenge or to gain influence over another. Sometimes both motives are operative. There is much to be said for this canonical understanding of alliance formation: it is intuitive and easy to grasp.

      Still, as shown in Chapter 1, although balancing power and influence-seeking can drive particular instances of alliance formation, these explanations are at best insufficient and may not even identify conditions necessary for states to agree to a military alliance. They indeed tend to overpredict how many alliances actually form. Most importantly, it is unclear why having a written alliance by way of a treaty is at all necessary for balancing power against adversaries or for projecting influence over would-be allies.

Writing down an alliance commitment accomplishes two strategic but seemingly contradictory tasks. One is that it allows signatories to communicate to international and domestic audiences that they have a serious stake in addressing a particular security challenge. Another is that it permits the signatories to leave purposely vague the conditions under which a treaty obligation would become operational, keeping both allies and adversaries in the dark as to what exactly would trigger a major defensive response. This vagueness is important in part because treaty allies have similar but not identical interests. Differences, just as much as commonalities, drive the need for written commitments. Treaties enable states to thread the needle more effectively between certifying a commitment for augmenting deterrence and allowing for enough ambiguity to keep allies and adversaries alike off balance. This in turn can lead the way for even more military cooperation because states become more comfortable about investing in their security relationship. Nevertheless, some alignments between states never rise to the level of a written commitment because their differences outweigh those commonalities too much.

Conventional wisdom #2: The alliance dilemma is a fundamental problem shared by all military alliances

      Scholars and observers frequently allude to something