At a time of fiscal constraint and global uncertainty, should the United States retrench geopolitically or seek to reinvigorate its international leadership? This collection of essays puts this pressing question in historical and theoretical context. The authors examine past episodes in which U.S. policymakers confronted similar choices, and draw insights from the strategies that they fashioned in response. The essays also consider the major theoretical and policy debates pertaining to the issues of retrenchment and renewal today.