Harry S. Truman (1884-1972) became the 33rd President of the United States upon the death of Franklin D. Roosevelt in April 1945. Truman, who had only a high-school education and had been in office as vice president for just 82 days before Roosevelt's sudden death, inherited the monumental task of leading the United States through the end of World War II and the beginning of the Cold War. Truman—who was, while in office, one of the least popular presidents in modern American history—won a surprising second term by defeating Republican Thomas Dewey in the election of 1948.
The Cold War began under Truman's watch, as the president came to believe that he must take a hard stance to contain the expansionistic tendencies of the Soviet Union. The president's "Truman Doctrine" committed the United States to a policy of supporting foes of Communism everywhere in the world. Truman's failure to lead the United States to victory in the Korean War led to a severe decline in support for the president's policies among the American people.