In this report, RAND researchers assess the evidence for claims that U.S. security relationships cause the United States to adopt its partners' interests, incentivize partners to behave recklessly, and risk dragging the United States into conflict.

The global system of alliances that the United States built after the Second World War underpinned the stability and prosperity of the postwar order. But during the 20th century, the multilateral NATO alliance system in Europe and the bilateral San Francisco alliance system in Asia rarely interacted. This changed in the early 21st century, as US allies came together to fight and stabilise conflicts in the Middle East and Central Asia. This volume presents the first-ever comparative study of US alliances in Europe and Asia from the perspectives of US allies: the challenges, opportunities and shifting dynamics of these fundamental pillars of order. This volume is essential reading for those interested in contemporary and future regional and global security dynamics.

The North Atlantic Treaty Organization (NATO) is the world’s largest, most powerful military alliance. The Alliance has navigated and survived the Cold War, the collapse of the Soviet Union, and the post-9/11 era. Since the release of the 2010 Strategic Concept, NATO’s strategic environment has again undergone significant change. The need to adapt is clear. An opportunity to assess the Alliance’s achievements and future goals has now emerged with the Secretary General’s drive to create a new Strategic Concept for the next decade—an initiative dubbed NATO 2030. A necessary step for formulating a new strategic outlook will thus be understanding the future that faces NATO. To remain relevant and adjust to new circumstances, the Alliance must identify its main challenges and opportunities in the next ten years and beyond. This book contributes to critical conversations on NATO’s future vitality by examining the Alliance’s most salient issues and by offering recommendations to ensure its effectiveness moving forward. Written by a diverse, multigenerational group of policymakers and academics from across Europe and the United States, this book provides new insights about NATO’s changing threat landscape, its shifting internal dynamics, and the evolution of warfare. The volume’s authors tackle a wide range of issues, including the challenges of Russia and China, democratic backsliding, burden sharing, the extension of warfare to space and cyberspace, partnerships, and public opinion. With rigorous assessments of NATO’s challenges and opportunities, each chapter provides concrete recommendations for the Alliance to chart a path for the future. As such, this book is an indispensable resource for NATO’s strategic planners and security and defense experts more broadly.

Since its creation in 1963, United States Southern Command has been led by 30 senior officers representing all four of the armed forces. None has undertaken his leadership responsibilities with the cultural sensitivity and creativity demonstrated by Admiral Jim Stavridis during his tenure in command. Breaking with tradition, Admiral Stavridis discarded the customary military model as he organized the Southern Command Headquarters. In its place he created an organization designed not to subdue adversaries, but instead to build durable and enduring partnerships with friends. His observation that it is the business of Southern Command to launch "ideas not missiles" into the command's area of responsibility gained strategic resonance throughout the Caribbean and Central and South America, and at the highest levels in Washington, DC.

Some of the most brutal and long-lasting civil wars of our time involve the rapid formation and disintegration of alliances among warring groups, as well as fractionalization within them. It would be natural to suppose that warring groups form alliances based on shared identity considerations - such as Christian groups allying with Christian groups - but this is not what we see. Two groups that identify themselves as bitter foes one day, on the basis of some identity narrative, might be allies the next day and vice versa. Nor is any group, however homogeneous, safe from internal fractionalization. Rather, looking closely at the civil wars in Afghanistan and Bosnia and testing against the broader universe of fifty-three cases of multiparty civil wars, Fotini Christia finds that the relative power distribution between and within various warring groups is the primary driving force behind alliance formation, alliance changes, group splits and internal group takeovers.

Is America’s alliance system so quietly effective that politicians and voters fail to appreciate its importance in delivering the security they take for granted? For the first century and a half of its existence, the United States had just one alliance—a valuable but highly controversial military arrangement with France. Largely out of deference to George Washington’s warnings against the dangers of “entangling alliances,” subsequent American presidents did not consider entering another until the Second World War. Then everything suddenly changed. Between 1948 and 1955, US leaders extended defensive security guarantees to twenty-three countries in Europe and Asia. Seventy years later, the United States had allied with thirty-seven. In Shields of the Republic, Mira Rapp-Hooper reveals the remarkable success of America’s unprecedented system of alliances. During the Cold War, a grand strategy focused on allied defense, deterrence, and assurance helped to keep the peace at far lower material and political costs than its critics allege. When the Soviet Union collapsed, however, the United States lost the adversary the system was designed to combat. Its alliances remained without a core strategic logic, leaving them newly vulnerable. Today the alliance system is threatened from without and within. China and Russia seek to break America’s alliances through conflict and non-military erosion. Meanwhile, US politicians and voters are increasingly skeptical of alliances’ costs and benefits and believe we may be better off without them. But what if the alliance system is a victim of its own quiet success? Rapp-Hooper argues that America’s national security requires alliances that deter and defend against military and non-military conflict alike. The alliance system is past due for a post–Cold War overhaul, but it remains critical to the country’s safety and prosperity in the 21st century.

Alliance politics is a regular headline grabber. When a possible military crisis involving Russia, North Korea, or China rears its head, leaders and citizens alike raise concerns over the willingness of US allies to stand together. As rival powers have tightened their security cooperation, the United States has stepped up demands that its allies increase their defense spending and contribute more to military operations in the Middle East and elsewhere. The prospect of former President Donald Trump unilaterally ending alliances alarmed longstanding partners, even as NATO was welcoming new members into its ranks. Military Alliances in the Twenty-First Century is the first book to explore fully the politics that shape these security arrangements – from their initial formation through the various challenges that test them and, sometimes, lead to their demise. Across six thematic chapters, Alexander Lanoszka challenges conventional wisdom that has dominated our understanding of how military alliances have operated historically and into the present. Although military alliances today may seem uniquely hobbled by their internal difficulties, Lanoszka argues that they are in fact, by their very nature, prone to dysfunction.