Virtually every analyst, pundit, and pollster predicted Dewey would win, perhaps by the same logic of people who bet "red" on roulette when black has come up four times in a row. (The Republicans just have to win sooner or later.)
Truman's chances were dimmed by a three-way split in the Democratic party: a progressive splinter group formed a party calling themselves the Progressives. (They were very liberal, but not so good at coming up with catchy names.) They nominated FDR's former VP, Henry Wallace. Meanwhile, conservative southern Democrats, calling themselves the States Rights Party or Dixiecrats - now, those are cool names, why can't liberals come up with names like that? - nominated Strom Thurmond. The States Rights Party championed conservative fiscal policies; specifically they felt allowing blacks into public schools and voting booths would damage the free enterprise system.
On the campaign trail, Dewey raised provocative, thought-provoking issues. The Lousiville Courier-Journal summed up the Dewey campaign message thus: "Agriculture is important. Our rivers are full of fish. You cannot have freedom without liberty. Our future lies ahead.” The Republican platform, daring and right-wing, called for an expansion of Social Security, more funding for public housing, and help from the federal government for health and education.1
On November 2, Dewey, his family, and staff stayed up all night in a New York Hotel listening to election returns. It was like waiting for Santa when Santa doesn't come. Although Truman had only 49% of the popular vote, he won by an electoral landslide, bringing the US its fifth consecutive Democratic administration.2
Harry S Truman:3 303
Thomas Dewey: 189
Strom Thurmond: 39
1. Republicans had been out of office for a long time and were very confused.
2. They were in the Roosevelt Hotel, which should have been a bad sign.
3. Harry Truman had no middle name. The "S" just stands for "S."