On february 10, 2004, I delivered the Irving Kristol Lecture to the American Enterprise Institute outlining a theory of foreign policy that I called democratic realism. It was premised on the notion that the 1990's were a holiday from history, an illusory period during which we imagined that the existential struggles of the past six decades against the various totalitarianisms had ended for good. September 11 reminded us rudely that history had not ended, and we found ourselves in a new existential struggle, this time with an enemy even more fanatical, fatalistic, and indeed undeterable than in the past. Nonetheless, we had one factor in our favor. With the passing of the Soviet Union, we had entered a unique period in human history, a unipolar era in which America enjoys a predominance of power greater than any that has existed in the half-millennium of the modern state system. The challenge of the new age is whether we can harness that unipolar power to confront the new challenge, or whether we rely, as we did for the first decade of the post-Cold War era, on the vague internationalism that characterizes the foreign policy thinking of European elites and American liberalism.

The speech and the subsequent AEI monograph have occasioned some comment. None, however, as loquacious as Frank Fukuyama's twelve-page rebuttal in the previous issue of the National Interest. His essay is doubly useful.