The United States is contending with the most challenging international environment it has faced since at least the Cold War and perhaps since World War II. One of the most disconcerting features of this environment is the burgeoning cooperation among China, Iran, North Korea, and Russia. Some policymakers and commentators see in this cooperation the beginnings of a twenty-first-century axis, one that, like the German-Italian-Japanese axis of the twentieth century, will plunge the world into a