This study intends to show that the United States adpoted a new strategy to guide its foreign policy in the post Cold War world. The Doctrine of Containment has oriented the American foreign affairs throughout the period of confrontation between the two superpowers. As a result of the end of the bipolar world, the United States has emerged as the world´s only superpower. In the post Cold War order, the new beacon of the United States foreign policy would be the strategy of Primacy. Since the fall of the Berlin Wall, the maintenance of the unipolar world has been the main objective of the American foreign policy.