Twenty-second Amendment to the United States Constitution
The amendment prohibits any individual who has been elected president twice from being elected again. Under the amendment, an individual who fills an unexpired presidential term lasting greater than two years is also prohibited from winning election as president more than once. Scholars debate whether the amendment prohibits affected individuals from succeeding to the presidency under any circumstances or whether it only applies to presidential elections.
Federalist No. 72
The twenty-second Amendment to the Constitution imposed the present two-tier term limit on the executive branch. Today, U.S. presidents can only serve two terms, or if a succession has taken place, ten years, as president of the country.