The Electoral College was developed by the framers of the Constitution as a compromise between allowing Congress to elect presidents and allowing the election through the popular vote. Under the system, each state is allocated the number of electoral votes equal to the number of its members in the House of Representatives, which depends on the state's population, plus the number of its senators from that state, which is fixed at two. The smallest states, as well as the District of Columbia, have three electoral votes.

All states, except for Maine and Nebraska, are "winner take all" states, which means that the candidate who receives the most votes gets all of the state's electoral votes. Maine and Nebraska, however, allocate electoral votes for each congressional district won and then give two electoral votes for the statewide winner.

Each state has electors who are party loyalists from both the...