TRUMAN, THE UNEXPECTED PRESIDENT
Nobody expected Harry S Truman to be president, least of all Truman. A last-minute compromise candidate as Franklin Roosevelt's third vice president, Truman had only a few months on the job when Roosevelt died. Truman said to reporters, "Boys, if you ever pray, pray for me now."
Truman was an honest man elected by a political machine, a failed men's clothing store owner who joined George Washington, Abraham Lincoln, and Andrew Jackson as a president who never went to college. When the love of his life turned him down when he first asked her to marry him, Truman went off, earned some money, fought in World War I, came back, and asked her again. This time she said yes.
As a senator before World War II, Truman took it upon himself to visit defense plants and push them to be more productive. The sign on his desk said, "The buck stops here"; Truman wouldn't stand for blame-passing. Counted out politically, he ran a give-'em-hell campaign and surprised everybody by winning the presidential election in his own right in 1948.
In his second term, Truman faced an icy freeze of relationships with the Soviet Union, which had been America's warm wartime ally when he first took office.
THE BEGINNING OF THE COLD WAR
The division of the world into the Soviet Union and its Communist allies against the United States and major capitalist free market countries in Europe and East Asia happened seemingly overnight at the end of World War II. People called it the Cold War (1950), although it got pretty hot in Korea and Vietnam.
World War II ended with the Soviet Union in control of Eastern Europe. The Soviets established Communist governments backed by Soviet troops in Poland, Czechoslovakia, Hungary, and other Eastern European nations. Winston Churchill said that an iron curtain (1946) had descended across Europe, dividing the free countries that had real elections from the Communist satellite countries ruled by party officials.
Don't get confused when countries change names. The Soviet Union, also known as the Union of Soviet Socialist Republics, also known as the U.S.S.R., was really just Russia with a few client nations on its outer edges that have since left the Russian Federation. When Russia went Communist after World War I, it took several (formerly partially independent) provinces and countries with it and became the Soviet Union . When it got over being Communist in the 1990s, it let some of the provinces go and went back to being called Russia.