This work is a study in strategic thought. Its objective is to demonstrate how the analyses and arguments of Carl von Clausewitz influenced American strategic thinking between the Vietnam War and the Gulf War. In addressing the influence of Clausewitz, one is examining the way in which his thought has been adapted to contemporary conditions. Clausewitz's conception of the state may place him in the realist canon but his writings do not ignore the irrational factors that are at work an international relations and war. By separating the "historical" Clausewitz from the strategically significant Clausewitz of today, the major similarity between the two rests on the basic assumption that war is an instrument of policy serving the state's interests. Unravelling the threads that make up American strategic thought is a high task. The idealistic strain in American strategy does not mean that expediency in the shape of balance-of-power politics is alien to the United States. As the only superpower to have exited throughout the whole post-war period, America's policy choices have been the major factor behind the shifting balance of the international security environment. Military power, even more so than the making and breaking of alliances, has been at its heart. Clausewitz was the first strategic theorist to seriously study the phenomenon of people's war. Ironically, the Vietnamese communists, despite their "Eastern" culture, showed more awareness than did the Americans of Clausewitz's thought. Their armed struggle occurred in tandem with a political struggle. The Americans found it difficult to clarify, for the sake of domestic opinion, the identity of the enemy. Without the commitment of the American people, the American military struggled to successfully execute a prolonged campaign in Vietnam. The Vietnam War is a classic case of the lack of grasp of policy at the strategic level being mirrored at the operational level precisely because the United States was unsure as to exactly the kind of conflict in which it was engaged.