The benign American world order launched by President Harry Truman in 1945 has contributed enormously to humankind, yet is likely to die in our lifetime. America and the West are neglecting it just as new challenges and new powers emerge. Alternative visions of the international system are abundant, from China's to the American neo-conservatives' to Osama bin Laden's. The vision behind the Truman world order remains the most powerful, and can still be salvaged. But the United States, as in 1945, must provide leadership and develop a new contract between America and the world. The principles for saving the postwar system are not difficult to find; the real challenge is to get America to abide by them.