About This Report iii

Summary v

Figures and Tables xi

CHAPTER 1 1

Introduction 1

  Why the United States Is Considering Further Retrenchment 2

  Debates About How Allies Would Respond 4

  Approach 7

  Report Organization 10

CHAPTER 2 11

Alternative U.S. Policies Toward Europe 11

  Commitments to Allies 11

  Military Posture 12

  Policy Toward Russia 13

  Tariffs on Allies 14

  Conclusion 15

CHAPTER 3 16

Threat Perceptions of Russia 16

  Drivers of Threat Perceptions 16

  Threat Perceptions Today 17

  How Future U.S. Policies Could Affect Allies’ Threat Perceptions 23

  Conclusion 25

CHAPTER 4 27

Relations with the United States 27

  Drivers of Ties with a Great-Power Patron 27

  European Cooperation with the United States Today 28

  How Future U.S. Policies Could Affect Allies’ Relations with the United States 39

  Conclusion 44

CHAPTER 5 46

Allies’ Ties with Russia and China 46

  Drivers of Policies Toward Rivals 46

  Allies’ Relations with Russia and China Today 47

  How Future U.S. Policies Could Affect Allies’ Relations with Russia 53

  How Future U.S. Policies Could Affect Allies’ Relations with China 55

  Conclusion 56

CHAPTER 6 57

Defense Spending 57

  Drivers of Defense Spending 57

  Allies’ Defense Spending Today 60

  How Future U.S. Policies Could Affect Allies’ Defense Spending 70

  Conclusion 72

CHAPTER 7 74

Regional Security Cooperation 74

  Drivers of Security Cooperation 74

  Regional Security Cooperation in Europe Today 77

  How Future U.S. Policies Could Affect Allies’ Regional Security Cooperation 83

  Conclusion 85

CHAPTER 8 86

Recommendations 86

  Develop and Coordinate with Allies on Long-Term Plans for Reductions in Peacetime Presence and Crisis Contributions, as Well as Force Structure Changes 87

  Take Tangible Steps to Implement This Long-Term Plan 88

  Encourage Deeper Regional Cooperation 88

  Avoid Leveraging U.S. Presence and Commitments for Secondary U.S. Priorities 89

  Accept That Promoting Europe’s Capacity for Self-Defense Could Mean That Allies Have Fewer Capabilities for Missions in Other Regions 89

  Support Allies’ Economic Growth 89

  Work with Allies to Promote a Durable Ceasefire in Ukraine 90

  Closing Thoughts 90

APPENDIX 92

Additional Details on Select Data Sources 92

Abbreviations 96

References 97

About the Authors 118