As leading Democrats compete for the nomination to battle with George Bush in the 2004 election, BBC News Online takes a look at some of the smaller parties hoping to make their mark.
Ross Perot - revitalised third-party politics in the US
The Greens will be hoping to repeat their impressive performance in the 2000 elections when nearly three million Americans voted for Ralph Nader. This time they will be without Mr Nader, who is standing as an independent.
The Green Party candidate is Texan lawyer David Cobb, whose platform is to "build a democratic movement that will take this country back from the corporate hooligans who have hijacked it from us".
The party founded by businessman Ross Perot to challenge Republican and Democrat dominance of US politics has been in something of a crisis in recent years. It never recovered from the splits that led to right-winger Pat Buchanan receiving the 2000 presidential nomination.
Mississippi businessman Ted Weill is the only candidate for the presidential nomination, running on a platform of ending foreign aid, lowering fuel prices and forcing prisoners to work.
Founded in 1971, the Libertarian Party is committed to "small-government", the free-market and a non-interventionist foreign policy. The party polled 0.36% of the vote at the 2000 election claims to be America's third largest.
US Presidential Vote 2000
Democratic Party - 48.38%
Republican Party - 47.87%
Green Party - 2.74%
Reform Party - 0.42%
Libertarian Party - 0.36%
Eight candidates are currently seeking the party nomination for president including former radio talk show host Gary Nolan. Nolan is campaigning for lower taxes, repeal of federal drug prohibition laws and an end to 'interfering in the problems of other nations' abroad.
The Constitution Party is also opposed to wide powers for federal government. The party is Christian, socially conservative and committed to creating a "republic under God".
Maryland lawyer Michael Peroutka is the party's provisional nomination for president. Peroutka has a long record of conservative activism and has pledged "to stand up against the entrenched socialists, elitists and globalists who presently have a stranglehold on American political power".
Natural Law Party
The NLP is attempting to bring a more spiritual, harmonious approach to American politics. The party promotes preventive health care, renewable energy and sustainable agriculture alongside 'peace-based' international relations.
Three-time presidential candidate John Hagelin has been encouraging NLP members to support Democrat nominee Dennis Kucinich in the primaries. This has led to speculation that Kucinich will become the NLP candidate if he fails to win the Democrat nomination.