Review for Quiz on Cold War Cold War – period of tension between the US and Soviet Union. Warsaw Pact – 1955 created a union of Communist nations in Eastern Europe in response to NATO. NATO – A union of democratic nations – collective security. Protect from the spread of communism. Iron Curtain – Churchill speech – referring to division of Europe – communism on one side and democracy. United Nations – An organization created to maintain peace and security between all nations. Containment – prevent communism from spreading to other nations. Truman Doctrine – Giving aid to Greece and Turkey so they don’t turn to communism.