The length of a U.S. presidential term is limited to 4 years, according to Article II, Section I, Clause I of the United States Constitution. Presidential terms were limited to prevent presidents from becoming too powerful.
Presidents are also limited to two terms in office. This rule was set up in the 22nd Amendment. When Article II was implemented, it never placed a limit on the number of terms a U.S. president could remain in office. Presidents such as George Washington and James Monroe voluntarily stepped down after two terms. It wasn't until 1940 that President Franklin Roosevelt decided to run for an unprecedented third term. After being elected a fourth time, Republicans rebelled and fought for the 22nd Amendment to be passed in Congress.