The Twenty-second Amendment (Amendment XXII) of the United States Constitution sets a term limit for the President of the United States. The United States Congress passed the amendment on March 21, 1947. It was ratified by the requisite number of states on February 26, 1951.
Franklin D. Roosevelt, who served from 1933 to 1945, is the only president elected to more than two terms. Under the 22nd amendment it would be possible for a president to serve two full four-year terms after having assumed the Presidency by means other than election for a duration of up to two years. No president besides Roosevelt has ever served more than eight years exactly, however.
''Section 1. No person shall be elected to the office of the President more than twice, and no person who has held the office of President, or acted as President, for more than two years of a term to which some other person was elected President shall be elected to the office of the President more than once. But this article shall not apply to any person holding the office of President when this article was proposed by the Congress, and shall not prevent any person who may be holding the office of President, or acting as President, during the term within which this article becomes operative from holding the office of President or acting as President during the remainder of such term.
Section 2. This article shall be inoperative unless it shall have been ratified as an amendment to the Constitution by the legislatures of three-fourths of the several States within seven years from the date of its submission to the States by the Congress.
Prior to Franklin D. Roosevelt, few Presidents attempted to serve for more than two terms. Ulysses S. Grant sought a third term in 1880 after serving from 1869 to 1877, but narrowly lost his party's nomination. Theodore Roosevelt succeeded to the presidency upon William McKinley's assassination and was elected in 1904 to a full term himself, serving from 1901 to 1909. He sought to be elected to a (non-consecutive) third term in 1912 but lost to Woodrow Wilson. In 1940, FDR became the first person to be elected more than twice; supporters cited the war in Europe as a reason for breaking with precedent. In the 1944 election, during World War II, he won a fourth term, but died in office the following year.
After Roosevelt's death, the newly Republican 80th United States Congress desired to establish a firm constitutional provision barring presidents from being elected more than twice. The rationale was a concern that without limits, the presidential position could become too similar to that of a benevolent dictator lasting not just four years but a lifetime, and that the position could become too powerful and upset the separation of powers. Hence, the Twenty-second Amendment was adopted.
While it is clear that under the Twelfth Amendment the original constitutional qualifications of age, citizenship, and residency apply to both the President and Vice President, it is unclear if a two-term President could later be elected—or appointed—Vice President. Some argue that the Twenty-second Amendment and Twelfth Amendment bar any two-term President from later serving as Vice President as well as from succeeding to the presidency from any point in the United States presidential line of succession. Others contend that while a two-term President is ineligible to be elected or appointed to the office of Vice President, he or she could succeed from a lower position in the line of succession which he or she is not excluded from holding. Still others contend that the Twelfth Amendment concerns qualification for service, while the Twenty-second Amendment concerns qualifications for election. Neither theory has ever been tested, as no former President has ever sought the Vice Presidency, and thus, the courts have never had an opportunity to decide the question.
Gerald Ford became president on August 9, 1974 and was in office for more than two years of the unexpired term of Richard Nixon. Had Ford won a full term in 1976 (he narrowly lost to Jimmy Carter), he would have been barred from being elected again despite only being elected once. No Vice President was elected to serve two full terms as President after assuming the Presidency after the death or resignation of a President. Theodore Roosevelt unsuccessfully sought a second term four years after serving a full term after succeeding William McKinley.
As of 2008, the following former Presidents are permitted to be elected for one more term: