Unit 7: Early Cold War By gavin.borgmann 1945 United Nations Formed 1947 22nd Amendment prohibits anyone who has been elected president twice from being elected again 1947 Truman Doctrine policy that gave military and economic aid to countries threatened by communism 1948 Berlin Airlift 1948 Marshall Plan program to help European countries rebuild after World War II 1949 NATO Established 1950 Korean War 1951 Rosenbergs Trial 1952 First H-Bomb detonated by the United States 1955 Jonas Salk invents the Polio Vaccine 1957 USSR Launches Sputnik