Containment

Containment, the foreign policy of containing Communism, was first introduced by George F. Kennan. Kennan was the ambassador to the Soviet Union, and through his "Long Telegram" he was able to interact with the United States, informing them about an up-rise in Communism, ultimately warning them to make sure that Communism would not spread globally. During this time, American society adapted the idea that both Capitalism and Communism could not coexist, therefore only one could come out victorious. In an attempt to preserve democracy, Joseph McCarthy, an extreme anti-communist American, felt that it was in America's best interest to cause hysteria in the nation, so that any alleged communists could be gotten rid of. In this day and age, being accused of being a communist meant that there was no clear, moral way of getting around such accusation. If you were called a communist, you'd be put in jail, unless you "confessed" of being a communist and named names of others who were communists. 

     

Eventually, Joseph McCarthy allowed the hysteria to get the best of him, and the overwhelming support he had accumulated from Americans subsided. McCarthy began to criticize the United States army, accusing the army of being contaminated with Communists. This caused and outrage, decreasing McCarthy's credibility and lessening the hysteria in the United States. 

The policy of Containment was predominantly implemented in  Korea and Vietnam, but namely in Vietnam. It became evident to the United States that if they allowed the Soviet Union to influence Vietnam with Communism, that this would then cause the "domino affect" where other countries would start falling to Communism, and then eventually, hypothetically subduing the United States. The U.S. was greatly passionate about intervention in Vietnam, however, this majority support was not enough to bring home victory. Vietnam eventually fell to Communism. Containment continued to prosper, up until Reagan's presidency, where Reagan advocated for a peaceful coexistence, allowing both the Soviet Union and the United States to prosper. Eventually, Communism destroyed itself in 1991, dissolving the Soviet Union; proving that Communism was unstable and incapable of lasting. 

Sources: https://en.wikipedia.org/wiki/Containment

https://en.wikipedia.org/wiki/George_F._Kennan