The United States's policy of containment had mixed results during this period. Direct involvement in the reconstruction of Japan and Western Europe prevented those areas from being communist. The United States also assisted anti-communist leaders in Italy and France in their attempts to maintain power. The United States also stood up to Soviet aggression when the Soviets tried to blockade Berlin in order to force the Western powers to give up all of Germany.
On the other hand, there were some marked failures. The United States stood beside Chiang Kai-Shek during WWII as he fought against the Japanese, and they stood with him during the war against Chinese communists as well. Even though the communists were known to be cruel, the Kai-Shek government was notoriously corrupt. Despite US aid, the communists still took China. The United States was able to stop North Korea from uniting the Korean peninsula under a communist flag, but only after a bloody war that ended in an armistice. The United States backed anti-communist regimes in South Vietnam even though the people who lived there hated Diem, the leader the United States backed.
United States intervention in Europe and Asia is a mixed bag during this period. When the United States devoted its full efforts, such as what it did with redrawing the Japanese constitution and the Marshall Plan in Europe, it achieved a successful result in stopping communism. When the United States attempted to roll back communism through covert action in the Baltic states and with Radio Free Europe, things did not go well. The Soviets attacked this incursion into their territory. The United States also fared poorly when it backed leaders only because they were not communists.
The United States was successful when major communist nations proved to be unwilling to go into total war in order to press their advantage, such as when the Soviets backed down during the Berlin crisis and the Chinese communists did not pursue the war after the armistice even though North Korean leadership agitated for years to receive more military aid. The role of anti-communist policeman was new to the United States and it would continue to evolve the role throughout the Cold War.