In the United States, the
Electoral College is the group of presidential electors required by the Constitution to form every four years for the sole purpose of voting for the president and vice president. Each state appoints electors under the methods described by its legislature, equal in number to its congressional delegation totaling 535 electors. The federal District of Columbia also has 3 electors under an amendment adopted in 1961. Federal office holders, including senators and representatives, cannot be electors. Of the current 538 electors, a simple majority of 270 or more electoral votes is required to elect the president and vice president. If no candidate achieves a majority there, a contingent election is held by the House of Representatives to elect the president and by the Senate to elect the vice president.