Presidents in the United States are chosen not by the popular vote, but through a system called the Electoral College.
Each of the 50 states and Washington DC has a set number of Electoral College votes that go to the candidate who wins a plurality of the popular vote there. The winner of the majority of the Electoral College’s 538 votes becomes the next president.
The number of electors in each state is determined by the number of officeholders that state has in the House of Representatives - proportional to the state’s population - added to the number of senators from that state. Each state has two senators, irrespective of population.
For example, California has the largest population of any state, 37 million people. It sends 53 members to the House of Representatives and two to the Senate; thus it has 55 electors.
The least populous state, Wyoming, with its 568,000 people, has only 3 electoral votes.
This indirect system of electing the president is enshrined in the US Constitution. It was instituted more than 200 years ago because the framers of the Constitution wanted elders to provide a check to the popular vote.
Consequently, the electoral system does not always reflect the will of the people. In 2000, Democrat Al Gore received more votes than Republican George W Bush, but Bush won in the Electoral College: 271 to Gore’s 266. Bush became the next president.
In all but two states, the candidate who wins the popular vote takes all that state’s electoral votes. Nebraska and Maine use proportional representation, allocating one electoral vote to the winner of each congressional district and two more to the winner of the statewide vote. In 2008, Nebraska actually split its electors for the first time, giving four electoral votes to Republican John McCain and one to Democrat Barack Obama.
The process of selecting electors varies from state to state, but generally, electors are party loyalists chosen at the state party conventions. The electors will meet on December 17 in their individual states to hold a ceremonial vote. Then the 113th US Congress will meet on January 3, 2013, to officially count up the electoral votes.
Each elector casts one vote for president and one for vice president. Twenty-seven states and Washington DC require electors to vote the way the people of that state vote.
In the unlikely event that the Electoral College ties 269-269, the House of Representatives would decide the next president and the Senate would vote for vice president.
But after 56 presidential elections, the Electoral College has only tied once. In 1800, the House of Representatives voted to make Thomas Jefferson the next president.