Twenty-second Amendment to the United States Constitution
As worded, the primary focus of the 22nd Amendment is on limiting individuals twice elected to the presidency from being elected again. Due to this, several issues could be raised regarding the amendment's meaning and application, especially in relation to the 12th Amendment, ratified in 1804, which states, "But no person constitutionally ineligible to the office of President shall be eligible to that of Vice-President of the United States". While it is clear that under the 12th Amendment the original constitutional qualifications of age, citizenship, and residency apply to both the president and vice president, it is unclear whether someone who is ineligible to be elected president could be elected vice president. Because of this apparent ambiguity, there may be a loophole in the 22nd Amendment whereby a two-term former-president could be elected vice president and then succeed to the presidency as a result of the incumbent's death, resignation, or removal from office (or even succeed to the presidency from some other stated office in the presidential line of succession).
Term limit
Many modern presidential republics employ term limits for their highest offices. The United States placed a limit of two terms on its presidency by means of the 22nd Amendment to the Constitution in 1951. There are no term limits for Vice Presidency, Representatives and Senators, although there have been calls for term limits for those offices. Under various state laws, some state governors and state legislators have term limits. Formal limits in America date back to the 1682 Pennsylvania Charter of Liberties, and the colonial frame of government of the same year, authored by William Penn and providing for triennial rotation of the provincial council, the upper house of the colonial legislature. (See also term limits in the United States).