The Twenty-Second Amendment
Ratified in 1951, the Twenty-Second Amendment limits any person to two elected terms as President of the United States. It wrote into the Constitution a two-term tradition that George Washington had established by example.
The original Constitution placed no limit on how many terms a person could serve as President. George Washington established a two-term tradition by retiring in 1796 after his second term. Thomas Jefferson followed his example, as did most subsequent presidents. The tradition held without exception for nearly 150 years. Franklin Roosevelt broke it. Elected in 1932 and 1936, he ran again in 1940 as the country prepared for war in Europe, and won. He won again in 1944. He died in office in April 1945, three months into his fourth term.
The political response was swift. Republicans had warned during the 1944 campaign that a fourth term would set a dangerous precedent. After they regained control of Congress in 1946, they moved to write the two-term limit into the Constitution. The Twenty-Second Amendment was proposed in March 1947 and ratified by the required three-fourths of the states in February 1951. The text is precise. No person may be elected to the office of President more than twice. A person who has served more than two years of someone else's term may be elected only once. The amendment explicitly did not apply to the sitting President, Harry Truman, though he chose not to seek reelection in 1952.
The amendment has shaped presidential politics ever since. Eight presidents have been elected to a second term since 1951. None has been able to run again. The lame duck status that begins in the second term has changed the strategic environment of the modern presidency. Critics argue that the amendment deprives voters of a choice they should be able to make and weakens a President at exactly the moment he should have the most political capital. Defenders argue that it codifies a republican principle Washington thought essential: no one person should hold so much power for so long. The amendment remains one of the few formal constraints on presidential ambition built directly into the constitutional text.