United States profile – Timeline Part 2 Jeraldine Belalcazar Garcia
World War II and the Cold War
1941 - Japanese warplanes attack US fleet at Pearl Harbour in Hawaii, leading to US joining World War II against the Axis powers.
1945 - US drops two atomic bombs on Hiroshima and Nagasaki. Japan surrenders.
1947 - US enunciates policy of aid for nations it deems threatened by communism in what became known as the Truman Doctrine. Cold War with Soviet Union begins.
1948 - America's programme to revive ailing post-war European economies - the Marshall Plan - comes into force. Some $13bn is disbursed over four years and the plan is regarded as a success.
1950-54 - Senator Joseph McCarthy carries out a crusade against alleged communists in government and public life; the campaign and its methods become known as McCarthyism. In 1954 McCarthy is formally censured by the Senate.
1950-53 - US forces play leading role against North Korean and Chinese troops in Korean War.
Desegregation and the Vietnam war
1954 - Racial segregation in schools becomes unconstitutional; start of campaign of civil disobedience to secure civil rights for Americans of African descent.
1960 - Democratic Party candidate John F Kennedy elected president, narrowly defeating his rival Richard Nixon.