How was the United States involved in the Vietnam War: The United States provided economic and limited military aid to prevent the spread of communism.. What was the name of the conflict involving nuclear weapons that almost erupted in October 1962 between the United States and the Soviet Union: Cuban Missile Crisis. Which senator proposed that citizens turn in their neighbor if they suspected the neighbor was a communist? : Joseph McCarthy . What is the term used to describe the invisible line that separated communist Eastern Europe from democratic Western Europe? : Iron Curtain . Read the passage. “After World War II, the U.S. and its allies formed an organization to assist each other. The countries supported the other members in diplomatic negotiations and military action. Their purpose was to ensure the security of member countries from outside threats.”What is the name of this organization? : . Study the picture.Front row left to right: Richard Nixon, President Eisenhower, Nikita KhrushchevWhat is the significance of the event in the picture: In 1959, Nikita Khrushchev became the first Soviet Union leader to visit the United States.. Read the passage.“During Harry Truman’s presidency, food and supplies were dropped to the people of Berlin, Germany. They were experiencing starvation because of blocks set up by the Soviet Union.”What was the "drop" called: Berlin Airlift. Which statement describes communism: a political and economic system in which the government owns and distributes wealth and resources. How was the Cold War different from previous wars involving the United States: