The term of office for President and Vice President is four years. George Washington, the first president, set an unofficial precedent of serving only two terms, which subsequent presidents followed until 1940. Before Franklin D. Roosevelt, attempts at a third term were encouraged by supporters of Ulysses S. Grant and Theodore Roosevelt; neither of these attempts succeeded, however. In 1940, Franklin Roosevelt declined to seek a third term, but allowed his political party to "draft" him as their presidential candidate and was subsequently elected to a third term. In 1941, the U.S. became involved in World War II, which later led voters to elect Roosevelt to a fourth term in 1944.
After the war, and in response to Roosevelt's shattering of precedent, the Twenty-second Amendment was ratified, barring anyone from being elected president more than twice, or once if that person served more than half of another president's term. Harry S. Truman, who was President when the amendment was adopted, and so by the amendment's provisions exempt from its limitation, also briefly sought a third (a second full) term before withdrawing from the 1952 election.