Answer: This answer is difficult. The United States fears communism, and set out to contain it around the world. During the Korean war, you could say the allies were successful containing communism due to the 38th parallel being created. But at the same time, they couldn't wipe communism out of all of Korea. The same goes for the Vietnam War. Another example is the failure of The Bay of Pigs invasion. The U.S failed in creating an uprising against the communist Fidel Castro. The U.S also could not keep China from becoming communist. But, you could say the Soviets failed in spreading communism because they were not able to spread it all across Europe.
Explanation: I hope this answers your question.