Franklin D. Roosevelt died on April 12, 1945, and Truman took over the presidency. He had no real clue that Roosevelt was so close to death and his succession came as a bit of a shock. As he told reporters the day after his inauguration, “[W]hen they told me what had happened, I felt like the moon, the stars, and all the planets had fallen on me.”

When the 1948 election year came around, the Democratic party was not sure that Truman could win reelection because in the 1946 midterm elections the Republican party had taken control of both houses of Congress, reflecting the public's opinions of his administration. However, in the end they did put their support behind him and nominated him to run with Alben Barkley as his vice president. He was opposed by Republican Thomas E. Dewey, Dixiecrat Strom Thurmond, and Progressive Henry Wallace. Thurmond and Wallace both had split from the Democratic party, so there was concern that they would each take votes away from Truman.

Truman campaigned vigorously, giving many “whistlestop” speeches from the back of a train car. His efforts paid off when, in the end, Truman won with 49 percent of the popular vote and 57 percent of the electoral vote.