The purpose of U.S. foreign policy is, at least theoretically, to keep Americans safe. Yet as we confront a radically changed world, it has become clear that the terms of that policy have failed. Washington's insistence on a market economy, its faith in the idea of the "West" and its "special relationships," its conviction that military primacy is the key to a stable and sustainable world order-these have brought endless wars and a succession of moral and material disasters. In a bold reconception of America's place in the world, informed by thinking from across the political spectrum, historian Andrew Bacevich lays down a new approach based on moral pragmatism, mutual coexistence, and war only as a last resort. Confronting the threats of the future-climate change, a shift in the international balance of power, and the rise of information technology as a weapon of war-his vision calls for a profound overhaul of our understanding of national security, setting out new principles to guide the once-but-no-longer sole superpower as it navigates a transformed world.