U.S. foreign policy has entered an era increasingly defined by debt and deficits. This provocative little book looks at the numbers and concludes that retrenchment is unavoidable. Mandelbaum paints a gloomy portrait of the massive and unsustainable budget deficits that have been generated in the last decade by generous tax cuts, expanded federal programs, and the war in Iraq -- pressures that, as Americans age and entitlement spending expands, will only get worse. These accumulated liabilities will begin to impinge on the United States' foreign policy spending and geopolitical commitments. It will be a new situation for U.S. policymakers, who have not had to think in terms of economic costs since the 1940s. Mandelbaum calls the impending scarcity of foreign policy resources an "unfortunate development," given the United States' long-standing role as a provider of global economic and security leadership. Not just American elites but the world, too, will need to adjust to the contraction of Washington's global role -- and Mandelbaum believes that this could lead to renewed great-power conflict as China, Russia, and other states compete to fill the vacuum. But he leaves as an open question what commitments and global roles the United States will need to cut.