So why have the candidates spent millions of dollars urging you to vote for them? Because in most cases, the 540 members of the Electoral College, called electors, are obligated to vote for the candidate who won the popular vote in their state or territory. In other words, the winner of the popular vote in a particular state gets all the state's electoral votes, even if he only won the state by a few votes. It is the electors' vote that technically decides the election, and a candidate must gain 270 electoral votes to win the White House.
In most elections, the winner of the popular vote also wins the majority of the electoral votes. But four times in our history, this has not occurred: in 1824 (John Quincy Adams), 1876 (Rutherford B. Hayes), 1888 (Benjamin Harrison) and 2000 (George W. Bush).
In this year's too-close-to-call election, it is possible that both George Bush and John Kerry could receive 269 electoral votes. What would happen then? The House of Representatives would decide who wins.