Who is the president of the united states?

The President and Vice President serve a term of office of four years. The Twenty-second Amendment (which took effect in 1951) provides that no one may be elected to the office more than twice, and that no one may be elected President more than once who has held the office of (or acted as) President for more than two years of another's term (thus a person may hold the office of President no longer than ten years--two four-year terms and one term less than two years having been a vice president who succeeded to the Presidency). Prior to the ratification of this amendment, and following the precedent set by George Washington, an unofficial limit of two terms was generally observed, with the only exceptions being Theodore Roosevelt, who ran unsuccessfully for a third nonconsecutive term, and Franklin D. Roosevelt, who served three full terms and died in his fourth after just over 12 years in office. Since the amendment went into effect, three Presidents have served two full terms: Dwight Eisenhower, Ronald Reagan, and Bill Clinton. Richard Nixon was elected to a second term but resigned before completing it. Current President George W. Bush will become the fourth should he complete his current term, on 20 January 2009. Lyndon B. Johnson was the only president since the ratification of the amendment to have been eligible to have served more than 2 terms, having served only 14 months of John F. Kennedy's term after becoming president following the latter's assassination. Harry S. Truman was also eligible for a potential third term as the 22nd specifically states it did not apply to the president in office upon its ratification (Truman). He briefly sought re-election in 1952, but withdrew after losing the New Hampshire primary.