According to the U.S. Constitution, the vice president has to be a natural-born citizen, to have resided in a U.S. state or territory for 14 years, and to be at least 35 years old. The constitutional qualifications for vice president are the same as they are for the presidency.
Candidates for vice president cannot run with a presidential candidate from the same state. Candidates for the vice presidency must be willing to take over the duties of the president if he is incapacitated, removed from office, or otherwise unable to meet the obligations of his office. If the vice president takes over presidential duties temporarily, he is not required to be sworn into office as president. If the vice president takes over presidential duties permanently, he must be sworn in as president, and another vice president is chosen. In the event that a vice president becomes president or is removed from office, another vice-presidential candidate can be nominated by the president and appointed to office once approved by a majority vote in both houses of Congress. Originally, the vice president was required to be elected by the people separately from the president. At first, the vice presidency was awarded to the person who received the second most votes for president. The law was changed in 1804 to allow the people to cast separate votes for the president and vice president, encouraging political parties to run candidates as teams.