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By 1945, World War II ended but a cold war emerged as the two remaining super powers of the United States and the Soviet Union became locked in a contest of competing ideologies—capitalism vs. socialism and democracy vs. totalitarianism. Tensions were evident in European nations such as Greece and Germany and in China. Much of the way America would conduct itself during the Cold War had its origins in the late 1940s.


February 4 -- A conference at Yalta, a city on the Crimean peninsula, begins, where the “Big Three,? FDR, Churchill, and Stalin, agree on the post-war reorganization of Europe.  Among other points, the United States and Great Britain accepted Soviet possession of eastern Poland, and free elections were promised (but never held) for Poland and other countries in Eastern Europe.

  May 8 -- World War II ends in Europe.
  July 17 -- President Truman attends a conference at Potsdam, Germany with Stalin and Churchill (later, Atlee) to discuss post-war Germany.  Here Truman learns of the successful testing of the atomic bomb and approves its use against Japan.
  August 6 -- United States uses the first atomic bomb against the Japanese city of Hiroshima killing upwards of 100,000 people in the blast.
  August 9 -- United States drops a second atomic bomb on the Japanese city of Nagasaki killing an estimated 40,000 - 70,000 people in the blast.
  August 14 -- Japan surrenders ending World War II.

February 22 -- U.S. diplomat to the Soviet Union, George Kennan, writes his “Long Telegram? to Washington, in which he warns of Soviet ambitions in Europe and argues for aggressive action to thwart their aims.

March 5 -- Winston Churchill speaks at Fulton, Missouri, declaring “…an iron curtain has descended across the Continent? (of Europe) Eastern Europe, “in what I must call the Soviet sphere….?
July 1 -- Operation Crossroads, Test Able, features a nuclear air burst at Bikini Atoll, Marshall Islands, in the Pacific Ocean.  This was the first public demonstration of America’s atomic arsenal and began a series of nuclear tests.
1947 March 12 -- President Truman declares the Truman Doctrine in asking for aid for Greece and Turkey to thwart communist expansion into these countries.
  June 5 -- The Foreign Assistance Act (Marshall Plan) is announced at Harvard by Secretary of State George Marshall.  Eventually, grants and loans totaling $14 billion would be made to Western European countries.
  July 26 -- President Truman signs the National Security Act, installing civilian department heads over military branches, establishing departments to aid the president in formulating and implementing foreign policy, and creating the CIA.

February 25 -- A coup begins in Czechoslovakia, undertaken by the Communist Party of Czechoslovakia and supported by the Soviet Union.


June 24 -- Soviets halt all road and rail traffic between Berlin and the West, effectively blockading the city from the ground, while President Truman and other Western leaders approve a plan to supply the city from the air.  Within a year, the American-led airlift effectively overcomes the Soviet blockade.


August 3 -- Whittaker Chambers, a former member of the American Communist underground, begins testifying before the House Un-American Activities Committee (HUAC) and names a former State Department employee, Alger Hiss, as having been a communist.  Eventually, Hiss would be confirmed as having been a Soviet spy.


April 4 -- North Atlantic Treaty (NATO) is ratified by the Senate and signed by President Truman.  It is the first peacetime military alliance in American history.  The United States and Canada join ten West European countries after the Europeans request the alliance in the face of the Czech coup and the Berlin blockade.

  August 29 -- Soviets detonate their first atomic bomb, Joe 1, estimated at between 10-20 kilotons.  Americans realize they no longer are the sole nuclear power in the world, and the arms race begins in earnest.

October 1 -- Mao Zedong, a Communist, announces the formation of the People’s Republic of China, effectively ending twenty years of civil war with Chaing Kai-shek and the Chinese Nationalists, who retreat two months later to the island of Taiwan.  Fears rise within the United States about a growing Communist monolith.