This book explores the transformation of the American-led alliances, as well as of US allies' responses to potential American disengagement from regional security amid the rising Russian and Chinese threats.

The post-Cold War international order has led to three challenges for the West. The first challenge was the ending of the Cold War, which had served as the fundamental rationale of the US-centred alliance systems in both Europe and Asia. The second challenge was that while the fear of US disengagement in the post-Cold War era was initially about its political willingness, the relative decline of the US has gradually turned the question into that of capability. And the third challenge is that for the first time since very long, a war in which one of the great (nuclear) powers is involved takes place on European territory. In Europe, the immediate consequence of the war has been a strengthening of NATO. In Asia and the Indo-Pacific, regional reactions to the war have been much more muted, for the division between "friends and foes" remains less clear-cut than in Europe. The chapters in this volume bridge the dynamics in the European and Asian theatres and provide a comparative framework for examining security alignments amid the shifting strategic context of the Indo-Pacific.

With 4 new chapters and a revised Introduction, this book will be of great interest to students and researchers of Politics and International Relations, Asian and European studies. The other chapters were originally published in Asian Affairs.

Elena Atanassova-Cornelis is Senior Lecturer in International Relations of the Asia-Pacific at the Department of Politics, University of Antwerp, and Professeur at the School of Political and Social Sciences, Université Catholique de Louvain, both in Belgium. Her research interests and expertise include international relations, security and strategic studies with a focus on Asia and the Indo-Pacific region, as well as Asia-Europe relations. She has authored numerous academic articles, book chapters, briefing papers and policy reports, and has vast experience in academic and executive teaching in Europe and Asia. She is the co-editor (with Frans-Paul van der Putten) of Changing Security Dynamics in East Asia: A Post-US Regional Order in the Making? (2014).

Yoichiro Sato is Professor at Ritsumeikan Asia Pacific University, Japan. He has published more than ten books including The U.S.-Japan Security Alliance (co-edited with Takashi Inoguchi and G. John Ikenberry, 2011), Regional Institutions, Geopolitics and Economics in the Asia Pacific (co-edited with Steve Rothman and Utpal Vyas, 2017), and Re-Rising Japan (co-edited with Hidekazu Sakai, 2017). His commentaries have appeared in various global media, including Time, Newsweek, Al Jazeera, Agence Presse Francais, and Nikkei Asian Review.

Tom Sauer is Professor of International Politics at Universiteit Antwerpen, Belgium. He is an expert on international security, and more in particular on nuclear arms control, and he is the spokesman of the university's Research Group of International Politics. He is the co editor (with Jorg Kustermans and Barbara Segaert) of Non-Nuclear Peace: Beyond the Nuclear Ban Treaty (2020); as well as the co-editor (with Brecht Volders) of Nuclear Terrorism: Countering the Threat (2016).