What does the amendment do?
Ratified in 1951, the 22nd Amendment says a person cannot be elected president more than twice. An amendment is a formal change or addition to the Constitution.
Why was it added?
For much of U.S. history, presidents followed George Washington’s example and stepped down after two terms. Franklin D. Roosevelt broke that precedent: voters elected him four times. After his presidency, Congress proposed a constitutional limit to restrict repeated reelection and the concentration of presidential power.
Does that always mean exactly eight years?
No. The rule limits elections, with a special rule for someone who takes over another president’s term. If that person serves more than two years of the other term, they can be elected only once. If they serve two years or less, they can be elected twice.