Forty years ago, when the world was plunging headlong toward total war, the Soviel Union was America's ally. Ten years later the same Soviet Union was being scorned as the home of “Godless communism” and the enemy of everything sacred to ihe “free world.” With the Cuban missile crisis of 1962. the two nations were facing each other across an abyss so large that nuclear war seemed a distinct possibility. Ten years after that, at the Moscow Summit of 1972. an American president with unimpeachable anti-Communist credentials was supping with yesterday's devil in the very capital of world communism; Nixon and his hosts managed to produce an “orgy of agreements” (the phrase is Max Frankel's), including the first Strategic Arms Limitation Treaty (SALT 1) and the start of an era called detente. Within six years another American president was announcing that “America is now free of the inordinate fear of communism.”