The Containment Theory.

The term containment describes the foreign policy strategy pursued by the United States after the Second World War. The term was introduced into the public debate by George F. Kennan, a diplomat and U.S. State Department adviser on Soviet affairs. In his famous anonymous X-article Kennan suggested a "long-term, patient but firm and vigilant containment of Russian expansive tendencies." The Strategy of Containment found its first application in the Truman Doctrine of 1947, which guaranteed …

…to break up sooner or later. The third goal was modification of the Soviet Concept of International Relations. Kennan's third goal was the most ambitious one, namely to lead the Soviet Union away from its universalistic notion of international affairs toward a particularistic understanding of reality. Kennan's concept of containment was based on his particularistic notion of U.S. foreign policy. Kennan's containment differed significantly from the containment U.S. foreign policy-makers would later practice.