How did containment policy guide American leaders as the Cold War emerged and moved through its initial stages in the late 1940s?

Despite the fraying relations with the USSR at Yalta and Potsdam, the FDR and Truman administrations assumed that somehow the Soviets could be brought along as postwar partners. By the winter of 1945–1946, however, the dream of postwar cooperation was being replaced by the new policy of “containment.” What was the policy of containment, and how did George Kennan originally articulate it? How did containment policy guide American leaders as the Cold War emerged and moved through its initial stages in the late 1940s? Finally, how did events and ideological reconsiderations lead to the much more expansive vision of containment outlined in NSC-68? In your essay, be sure to show awareness of relevant primary source readings.The paper should include an intro, supporting paragraphs, and a conclusion.