Discuss the Doctrine of Containment: how did it originate? What was the debate over its usefulness and Soviet Intentions? What are three examples of the Containment policy in the period 1946–1989?

Historians trace the origins of containment policy to the ideas of George Frost Kennan, articulated in the Kennan Long Telegram, written for the State Department under the Truman administration in February 1946, and a subsequent article in the journal Foreign Affairs under the pseudonym of "Mr. X" formally entitled, "The Sources of Soviet Conduct."
Kennan's telegram and article came at a time when the Truman administration was plotting its foreign policy course vis-a-vis the Soviet Union, after having been on the same side with the communist country in World War II. Some American politicians, most notably the Progressive Party's Henry Wallace, believed that cooperation with the Soviet Union in the postwar period was possible, whereas others disagreed and, to varying degrees, played up the Soviet menace. In a word, Kennan argued that communism is inherently expansionistic and, therefore, the best strategy is to try to contain it or stop it from spreading. Although Kennan claimed for the rest of his days that his notion of containment was a political and cultural one, the Truman administration militarized it, which contributed to the development of a nuclear arms race.
Since containment was the key element of American foreign policy during the Cold War, an abundance of examples of its application might be cited, including the Truman Doctrine, the Marshall Plan (or European Recovery Program), NATO (North Atlantic Treaty Organization), the Korean War, the Bay of Pigs invasion of Cuba, the Vietnam War, and Operation Cyclone during the Soviet-Afghan War. Each of these has been documented by historians and can be productively examined within the context of containment doctrine.
https://www.history.com/this-day-in-history/henry-wallace-criticizes-trumans-cold-war-policies