Rather it is based on a complex system put in place by the US constitution to guarantee that the winner has a wide democratic mandate.

This system is called the US Electoral College. It chooses the president and vice-president of the United States at the end of every presidential election.

When Americans enter the poll booths of their home state every four years to elect a president, they cast a ballot for electors from a political party which has nominated a candidate to run for president.

The electors later vote for the person a citizen has marked on the ballot paper they want to be president.

The number of electors in each state is equal to the number of senators (two per state) plus the number of US representatives, which varies according to the state's population as determined by the census count every 10 years.

Currently, the Electoral College has 538 electors - 535 for the total number of senators and representatives plus three for Washington DC.

A candidate must receive 270 electoral votes to win.

The electors meet in their state capitals to cast their votes for president and vice-president on the Monday after the second Wednesday in December. This time delay has been provided for by the constitution in the case of a recount, after a contested election.

The votes are sealed and sent to the president of the Senate (who is the vice-president of the United States).

The Senate president opens and reads them before Congress on 6 January, thus officially announcing the winner.

Why the electoral college?

The founding fathers of the US constitution wanted to put in a compromise to the mechanism used to choose a president.

The system's founders feared a
direct, winner-take-all election

The founders feared a direct, winner-take-all election. Since travel and communication around the country was slower in those days, they were concerned that citizens would not get sufficient information about candidates outside their state and would usually just pick someone from their region.

With a direct popular vote, it is more likely that no candidate will receive a majority sufficient to govern a whole country, making challenges more frequent.

Even if there was a clear winner, the selection of the president would often be decided by the biggest, most populous state with little attention paid to smaller ones.

The Electoral College was the compromise which would ensure the president had a wide geographic mandate.

Who are the electors?

State legislatures decide the manner by which electors are chosen and methods vary according to the state.

In 1984, Ronald Reagan was
re-elected in a landslide vote

The two most common ways are when either an elector is nominated by his or her state party committee (usually as a reward for years of commitment to the party) or the elector "campaigns" for the spot and a vote at the party's convention decides the winner.

There is no federal law that requires electors to vote how they pledged they would. And there have been a few instances where electors have not supported their party's candidate or the state's popular vote.

In the past, electors have done this to make a statement when the election was not close and their vote would not matter, such as in 1984 when four electors pledged to Republican candidate Ronald Reagan voted against him.

Reagan was re-elected in a landslide vote.

The 12th amendment

As in 2000, which became a highly contested election with the decision ultimately decided by the Supreme Court, the 12th amendment dictates that if one candidate does not win the 270 electoral votes to become president, the decision goes to the House of Representatives, where each state has one vote.

The house vote is by state delegations, not simple majority, and the winner must get the vote of 26 state delegations.

Assuming the states follow party lines, there are currently 30 Republican delegations, 16 Democratic delegations and four deadlocked delegations.

This current formula would guarantee Bush victory.