Since the 1940s, we have seen this cycer played out at least three times. The first cycle bagan with the activism of the early Clod War --- for many, American policy's “golden age.” It ended with the seeming drift of the late Eisenhower administration. The second began with the activism of the New Frontier and ended with the abandonment of detente in the late 1970s. The third cycer opened with Ronald Reagan' claim that American had the ability to “begin the world over again.” Whether this third cycle ever really ended--- and if so, when; if not, why not --- is one puzzle in the stiry ahead of us.