The race for the White House has begun in earnest. It is a long process, but one that follows a set of familiar steps.
In early September, the Democratic party signalled the start of the race to find its standard bearer with a live debate between the party's contenders.
Since then the contenders have been taking part in a series of debates in an attempt to win support before the beginning of what is known as the primaries. This is when Democrats go to the polls to nominate a candidate.
Democratic contenders will take part in a series of debates
This time around, Republicans will not need to go through this process because no party opposition to George W Bush is likely to emerge. His focus over the next few months will be fundraising.
The next few months will see a lot more television advertising for the Democratic contenders as well as aggressive fundraising.
Primaries will begin in late January. Voters will cast a ballot for a slate of delegates who are usually pledged to a party contender. The contender who wins the most delegates across the nation wins.
This, however, is not confirmed until the party's national convention in the summer, which the delegates attend.
While most states hold primaries, some hold what are known as caucuses to nominate a candidate. A caucus is more complex than a primary.
No Republican challenger to Mr Bush is likely to emerge
It is a multi-stage process that tends to start at grassroots, precinct level and proceed through stages to a state convention.
The states of Iowa and New Hampshire will officially kick off the process to choose delegates, with the former holding caucuses on 19 January 2004 and the latter a primary eight days later.
This time around, primaries are characterised by what is known as frontloading, which means that a huge number of primaries are being held over a short period of time.
There has been a trend over past election campaigns for states to hold their primaries earlier and earlier to try to increase their influence in the nomination process.
This time, because so many are being held during February, the Democratic nominee could emerge early on, possibly in late February.
Between the end of the primaries and the party national convention, the candidate who is believed to have won the nomination will spend months bolstering their campaign organisations and placing key people where necessary.
He or she will also scout around for a vice-presidential running-mate.
The Democratic National Convention will take place in Boston in the week of 26 July, while the Republican National Convention will take place in New York between 30 August and 2 September.
Party conventions are the great set pieces of American politics
The conventions are one of the great set pieces of American politics. They are the one occasion when, in order to nominate their presidential and vice-presidential candidates, the entire national party comes together for a mixture of politics and partying.
On the last night the presidential candidate gives his big speech - a key opportunity to outline to the nation the major themes of his campaign.
Because of the extensive media coverage, candidates usually get a bounce out of their convention - a rise in their standing in the polls.
The official campaign between the Democratic and Republican rivals begins when the conventions are over. There will be heavy spending on nationwide television publicity and the two challengers will likely square up in a series of televised debates.
Tens of millions of people tend to watch these debates, some of which take place within a month of the elections.
The nation will vote in a general election on 2 November, 2004.