The question on every Democrat's lips: should she stay or should she go?

In the garden across the street from where I am writing, in this overwhelmingly Democratic city of Washington DC, stands an oddity. It is an election poster for Hillary Clinton, outnumbered 10 to one in the neighbourhood, I would guess, by signs for Barack Obama.

Tiny samples do not a trend make. But the disparity is a reflection on the mood in the party. For the Democratic establishment, the once exhilarating struggle for its 2008 nomination has turned into a brutal, protracted and demoralising brawl, from which even the winner will emerge a loser.

The dread is palpable. Are we going to mess up and yet again snatch defeat from the jaws of victory? Is this historic contest, that we thought would move America into a new era by propelling either a woman or a black man into the White House for the first time, turning into a nightmare that re-opens America's ancient wounds of race and gender? Please, they beg, let it end soon. And many then turn towards Clinton and ask: please do the decent thing, place the party ahead of personal ambition and withdraw, to ensure victory over the real enemy – the Republicans – in November.

But why, one might wonder, is she being asked to fall on her sword, when nothing has been decided? Mainly, of course, because, after primaries and caucuses in more than 40 states, she trails in the number of pledged delegates to the convention (by roughly 1,480 to 1,590), in total votes won, and in the majority of preference polls among Democratic voters. Moreover, by a margin of almost two to one and regardless of personal preference, these latter expect Obama to be the party's nominee.

Another reason is the present seven-week hiatus between primaries (the last was on 11 March in Mississippi, the next not until 22 April in Pennsylvania). Of late she has won no votes, but many bad headlines. Third, and not least important, she is Hillary Clinton, one half of simultaneously the most accomplished and most divisive couple in American politics.

Were Obama in her position, I suspect few would be too concerned that the race was still continuing. But a Clinton, whether named Bill or Hillary, is different. Rightly or wrongly, they are perceived as obsessed with personal victory, whatever the cost to others, even their own party. The longer and harder the fight, the more likely, it is assumed, they have some devilish ploy up their sleeve.

And the fight is growing harder. The polls suggest that the Illinois senator, not least thanks to his stunning speech on race a few days before Easter, has weathered the tempest let loose by the rantings of his pastor, Jeremiah Wright.

Clinton, in the meantime, has made a sublime ass of herself. Those boasts about dodging sniper fire in Bosnia (part of her laughable efforts to show she is more experienced than her rival) were bad enough. Almost worse was her claim, when her deceit was rumbled, that she had "misspoken" – a formulation first patented by Ron Ziegler, Richard Nixon's hapless press secretary, during the Watergate scandal.

But is this enough to demand that she withdraw from the race forthwith? A few weeks ago in this space, I set out Clinton's case for staying in, and that case hasn't changed much since.

In the first place, it ain't over till it's over. This is a desperately close contest in which neither candidate can any longer secure the 2,024 delegates needed to win from the primaries and caucuses alone. He or she will need the support of the "superdelegates", some 800 Democratic grandees who may cast their votes as they please. Their creation may have backfired disastrously, ensuring the possibility that a candidate who has won fewer primaries and a smaller share of the popular vote can still prevail. But Clinton did not invent this rule. Who can now blame her if she tries to exploit it?

Second, why should she withdraw three weeks before a major primary in Pennsylvania, which she is expected to win? Assume she does, and that the momentum carries her to victories in the next primaries, in Indiana and Kentucky – who knows, maybe even in North Carolina, a state which, with its substantial black population, has hitherto looked good for Obama.

Thanks to the proportional distribution of pledged delegates, it is mathematically impossible for Clinton to overtake Obama. But if he were to end the primary season in early June on a losing streak, his lead shrinking both in terms of delegates and the overall vote, then it is not unreasonable that the superdelegates take an unsentimental look at which candidate is best placed to recapture the White House in November. That, after all, is why they were invented in the first place.

Finally, despite the anguish, there is no rush. If Clinton were to lose in Pennsylvania, full of elderly, female and white blue-collar workers among whom she does well, then the game would be up – even for Bill and Hillary Clinton, with their ability to outdo Dracula in surviving stakes through the heart. If not, however, then let the battle continue.

After all, "somebody's going to lose this race with 49.8 per cent of the vote", as Howard Dean, the chairman of the Democratic National Committee, put it. He suggested last week that superdelegates should make up their minds by 1 July, and thus settle the nomination. That would still leave almost two months for the winner to take a long-overdue holiday, select a running mate and organise a glitzy coronation at the Denver convention in the final week of August.

That, however, is not how a jittery Democratic establishment sees things. It is terrified that the ever more poisonous feuding between the two camps is splitting the party by race, class and gender, threatening to throw away its most winnable presidential election in more than a generation and perhaps even jeopardising the party's recently won control of Congress.

At one level, such fears are easy to understand. In putative match-ups, John McCain now beats both Clinton and Obama, the polls say, despite the huge lead Democrats enjoy in the "generic" vote. While the all-but-certain Republican nominee travels to Baghdad, plays the statesman at 10 Downing Street and makes lofty speeches about foreign policy, his foes toss grenades at each other.

In the meantime, McCain's gaffes pass almost unnoticed, for instance the recent assertion – by a man who has built his campaign on expertise in foreign affairs – that Iran has been helping al-Qa'ida insurgents in Iraq. Mis-speaking is not a Clinton monopoly.

Not so long ago, Democratic voters professed themselves delighted with their choice of candidates, no matter who won the nomination. No longer, it seems. According to a Gallup poll last week, 28 per cent of Clinton supporters say they will vote for McCain if Obama is the nominee, while 19 per cent of Obama backers insist they will do the same in the event of a Hillary victory. If that pattern held, the Republican would be a shoo-in at the general election.

But, almost certainly, it won't hold. Assuming Dean's very reasonable target date is met, the party will surely regroup. At that point, as economists like to say, the fundamentals will reassert themselves.

Leave aside the war in Iraq, unpopular as ever but temporarily forgotten amid the mortgage crisis. The biggest fundamental of all is the economy. Republican laissez-faire policies and excessive deregulation are widely blamed for having got the US into its present mess. The lesson of economic crises past is that the party in power loses – be it 1932, the mid-1970s oil shock, or even the mild recession of 1990-91, after which the mantra of "It's the economy, stupid" propelled Bill Clinton to victory in 1992. McCain must cope with all this, even as Democrats hang around his neck the albatross of the younger Bush, whose approval ratings have hit an all-time low of 28 per cent.

If Obama wins, some fear a repeat of 1980, when the so-called "Reagan Democrats" – above all, white blue-collar workers – switched sides in droves, sealing Jimmy Carter's defeat.

But there is one colossal difference. Back then a Democratic era was drawing to a close. This is a Republican sunset, as public opinion shifts to favour a bigger role for government, demanding intervention at home to deal with the economy, education and healthcare, rather than on battlefields abroad. Come November, today's Obama/Clinton tribulations may be seen as a brief darkness before the new Democratic dawn.

CAMPAIGN DIARY
A busy week for mis-speak

* Sunday More than three-quarters of adults in the US report following the 2008 presidential campaign "very closely" or "somewhat closely", according to a survey.

* Monday CBS airs footage of Clinton calmly taking part in an arrival ceremony, on her 1996 visit to Bosnia. Clinton had previously claimed she landed under "sniper fire" and that the ceremony was abandoned.

* Tuesday Clinton admits she made a mistake in the above claim, saying it proved she was human.

* Wednesday Obama publishes tax returns covering the last seven years on his website.

* Thursday McCain warns that the withdrawal of US troops from Iraq could lead to "genocide".

* Friday Democratic Party chairman Howard Dean says he would like to see the nominating contest decided by 1 July.

* Saturday Pennsylvania senator, Robert Casey, endorses Obama's campaign, in time for the 22 April primary.

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