The success of the U.S. Containment policy is problematic at best. The doctrine, expressed by George F. Kennan, former U.S. Ambassador to the U.S.S.R. was to literally "contain" Communism, and prevent its further spread. On the ground, it was quite effective. The Berlin Airlift prevented the fall of that city to Communism; and the Korean war prevented unification of Korea under a Communist regime. Similarly, the unification of Viet Nam under a communist government was postponed for a number of years, although it did eventually happen.
The problem is the cost of containment. The policy was a major factor in the eruption of the Cold War and the development of a bipolar world in which every dispute, even among third world countries, became couched in terms of East vs. West. This included not only the Cuban Missile Crisis but the early Middle Eastern conflicts in which the U.S. and Soviet Union supported opposing sides. One must remember that the two Koreas remain officially in a state of war, so nothing was realized. Also, it was containment that led the United States to involve itself in Viet Nam with disastrous results. On another note, the entire arms race and the concept of mutually assured destruction may not have played out as it did were it not for the policy of Containment.
Some of this information is outside the time frame, but you should be able to connect it easily enough. My thesis would be that it prevented the further expansion of Communism to other countries outside the Soviet Bloc; but also led to the Cold War and U.S. involvement in both Korea and Viet Nam. Hope this helps.