11.   George Washington set the precedent for how long a president should serve by stepping down after his second term.

12.   Haitian presidents served only with the approval of American officials during the occupation.

13.   He added that some schools, such as Cornell University, traditionally have the president serve as commencement speaker.

14.   In addition to McKinley, only two other presidents had served in the enlisted ranks, according to several presidential reference books.

15.   In American government, he added, the president must serve as more than just a political leader.

16.   Is it possible for a president to serve two terms, sit out for four years, and then run again?

17.   It has also decided that the new president must have served in the armed forces.

18.   Mexican presidents serve one six-year term, and are constitutionally barred from a second consecutive term.

19.   Presidents serve a one-year term but are customarily re-elected once.