Democratic losers keep talking but fail to answer big question: why?

Three candidates who do not matter, running in a primary that does not matter, held a debate in Washington DC yesterday. They offered plenty of policy prescriptions, but not an answer to the real question: why are they competing for a Democratic presidential nomination they cannot win?

For America's political insiders, The Rev Al Sharpton, Carol Moseley Braun and Dennis Kucinich are little more than irritants, demanding time at debates and space on news pages that would be better devoted to the six "serious" contenders with a genuine chance of victory. Apart from Mr Kucinich, they have not raised significant money. With the exception of the Mr Sharpton in South Carolina, their support is negligible. Yet they further clutter a field that, even limited to six, would be tangled enough. Their appearance at George Washington University was a symbol of their marginal status. In fact, it is the District of Colombia, not Iowa or New Hampshire, which is holding the first primary on 13 January.

The debate, devised to press the campaign for DC statehood, was been shunned by the Big Six, five of whom have even removed their name from the ballot. The primary is also non-binding, meaning that no actual delegates will be chosen for July's Democratic convention in Boston.

But, in separate ways, each of the three has a subtle influence on the campaign, and each has good reason to pursue their quest to a probably little noticed end. Indeed, low expectations and shoestring field operations mean they will probably survive longer than bigger fish such as Richard Gephardt, Joe Lieberman or John Kerry, for whom defeat in the early primaries would be financially disastrous.

Of the three, Mr Kucinich is being taken most seriously. He decided to run in mid-2002, driven by outrage at the bellicose foreign policy of the Bush administration, the treatment of detainees at Guantanamo Bay and the threat to civil liberties embodied in Attorney General John Ashcroft's Patriot Act. It is tempting to dismiss him as a flake; the "boy mayor" of Cleveland at 31 in 1977 and the youngest person elected to run a major US city; so full of himself that he sacked his police chief live on television.

Mr Kucinich was sacked by the voters after only two years. He then headed west, became a vegan and acquired spiritual advisers. His campaign has been endorsed by the singer Willie Nelson. His campaign is run by a 'transformational kinesiologist', a healer through movement, without experience in politics. He has raised $5m (£2.7m) for the campaign and has a solid core of support on the radical left.

Ms Moseley Braun is another veteran of Capitol Hill, elected in 1992 from Illinois to become the first (and, so far, only) black woman to win a seat in the US Senate. But she was defeated in 1998 after a single term by a little known Republican; no mean feat in a state which grows more Democratic with each electoral cycle.

Ms Moseley Braun's downfall was due to a string of ethics controversies, ranging from meetings with a murderous Nigerian dictator to allegations of improper use and reporting of campaign funds. None were ever proven.

Mr Sharpton comes across as what he is: a flamboyant activist. In the set-piece debates, he is the funny one, getting off good-natured one-liners to deflate his rivals. But his candidacy has another very serious purpose, to cement himself as successor to Jesse Jackson as leading spokesman for black America.