THRILLED by the mess the Democrats are making of their presidential nomination contest, Rush Limbaugh, the right-wing radio rabble-rouser, has hit upon a wizard wheeze.

He has urged Republicans to register themselves as Democrats in the key primary state of Pennsylvania, and “if they can stomach it” to cast a vote for Senator Hillary Clinton.

The aim, says Limbaugh, is to help Clinton prolong the primary race as long as possible, thereby ensuring a Democratic bloodbath at the party’s nominating convention this summer, and handing the White House to Senator John McCain, who is certain of the Republican nomination. Limbaugh has dubbed his plot “Operation Chaos”.

Pennsylvania officials have reported a surge of voter registration, with almost 15,000 new Democrats signing up in one week.

Whether or not Limbaugh’s mischief-making is responsible – “They are in the midst of tearing themselves apart right now,” he said happily – the battle for the Democratic nomination shows no sign of easing up.

Storming across Indiana on Friday, Clinton shrugged off complaints by party leaders that her increasingly bitter struggle against Senator Barack Obama is playing into Republican hands and jeopardising the Democrats’ chances of regaining the White House in November.

“There are some people who are saying, you know, we really ought to end this primary, we just ought to shut it down,” she told a crowd in Mishawaka, Indiana, which votes on May 6. Clinton’s supporters cried: “No! No!” and cheered wildly when she pledged to remain in the race.

Clinton’s refusal to back down in a contest that many Democrats believe she can no longer win followed a week of venomous insults, belligerent manoeuvring and rare intrigue as party leaders sought an early end to a mesmerising but destructive primary spectacle.

“We cannot go five more months with the kind of daily sniping that’s going on,” warned Senator Christopher Dodd, a Connecticut Democrat.

“We don’t want this to degenerate into a big fight at the convention,” added Howard Dean, the party’s chairman.

Even Obama acknowledged that the primary race resembled “a good movie that lasted about a half-hour too long”.

After a series of secret meetings and late-night conference calls with senior party officials, Dean acknowledged last week that the acrimonious rivalry had become “unhealthy” and should not be allowed to drag through the summer unresolved until the nominating convention in Denver in late August.

Yet the party remains badly divided over attempts to force an early result. Clinton aides are furious that the New York senator is being pressed to step down while votes are still being cast and the prospect of a convention upset remains. Clinton told her staff last week that she would not be “bullied” out of the race.

Behind the surge of internal feuding lies a Clinton blunder that some officials believe has fatally undermined her chances. The revelation last week that Clinton had falsely claimed to have come under sniper fire while visiting Bosnia in 1996 as first lady earned her national ridicule and reminded Americans of her husband’s inconsistent record on telling the truth.

Almost 1m people viewed a spoof internet video that showed old news footage of her uneventful visit, with explosions and rocket fire imposed on the film.

More damagingly, the sniper fiasco effectively negated her gains from the controversy over Obama’s association with the Reverend Jeremiah Wright, the radical Chicago preacher who has repeatedly declared: “God damn America.”

Obama’s aides were quick to suggest that Clinton’s lapse followed a pattern of embellishment and misrepresentation. Clinton’s staff fired back that Obama had exaggerated aspects of his own past: he once claimed to be a law professor when he was really a lecturer.

“What’s going on is a food fight, personal attacks,” complained Bill Richardson, the New Mexico governor who recently endorsed Obama.

At the heart of the stand-off is the mathematical race to acquire the 2,025 delegates needed to secure the nomination in a convention vote. Obama currently leads Clinton by 1,628 to 1,497, and the outcome of the vote is likely to be decided by almost 800 “superdelegates”, party officials who are not formally committed to any candidate.

Hillary’s hopes of attracting superdelegate backing appear to rest on a thumping victory in Pennsylvania, which votes on April 22, and a blazing finish in Indiana, North Carolina and other smaller states that have not yet voted. With a series of victories under her belt, her aides argue she would be able to convince the superdelegates that she is best placed to take on McCain, especially in larger industrial states.

Yet the most recent opinion polls have been of little comfort to Clinton. Obama appears to have recovered from a Wright-induced slump, and last week he won another valuable endorsement, from Senator Bob Casey of Pennsylvania, where Clinton has been running strongly.

Hillary remains ahead in Pennsylvania, but her lead among blue-collar workers has been shrinking and on Friday Obama launched a six-day bus tour blitz of the state. He has also regained his lead in North Carolina and was eight points ahead of his Democratic rival in a national Gallup tracking poll on Friday.

It was a different story against McCain, who led Obama by up to seven points in tracking polls. Democrats fear that whoever they end up choosing, they will fall further behind McCain if the Clinton-Obama slugfest continues to dominate the headlines.

Party officials acknowledged last week that unless Clinton slumps to a surprise defeat in Pennsylvania, there is little prospect of intervention until after the final primaries on June 3. One senior strategist who has been neutral in the contest said he believed that Al Gore, the former vice-presidential candidate and winner of the Nobel peace prize, was “ideally positioned” to intervene at that point to persuade one of the candidates to step down.

“If Al and a bunch of party leaders – Nancy Pelosi [speaker of the House of Representatives], Dean, a couple of senators – call a meeting of superdelegates in June and urge them to pick a winner, there will be a huge fuss for a couple of days, but then this darned mess will be over,” the strategist said.

Dean said he hoped the contest nomination would be settled by July 1, which for some Democrats feels like a very long time.

No wonder Limbaugh is laughing: last week his website was selling “Operation Chaos” T-shirts for $19.95 each.

Bare-chested, gunslinger candidates are the voters’ dream

Many Democrats dream of the day that Barack Obama will become president. Others just dream of Obama, and then publish the details online.

An unusual trio of weblogs is appealing to American voters to provide details of any dreams they have had of the leading candidates in the presidential race. A law student from Brooklyn claims on the I Dream of Barack blog that Obama appeared in one of his dreams wearing green dreadlocks and ripping off his T-shirt.

A young female student dreams that she is Michelle, Obama’s wife. An unemployed man pictures him wrestling Osama Bin Laden to the ground and biting off his ring finger.

At the I Dream of Hillary blog, a Colorado man dreams he is shooting at Clinton, who shoots back. A 60-year-old male art critic dreams of Clinton on a water bed. More than 100 dreams have been posted to each site so far this year.

There is a similar blog devoted to John McCain, the Republican candidate, but the 71-year-old Arizona senator does not seem to be much of a dreamboat.

Only seven dreams have been posted at I Dream of McCain. One imagines him at the zoo in his underwear.

Following are a series of videos posted after Hillary's false claims last week

VIdeo: Headzup: Hillary Clinton In Bosnia

Video: Hillary WASN'T LYING! Bosnia gunfire footage discovered...

Video: More of the Clinton's mis-statements exposed

Video: New Footage of Clinton in Bosnia

Video: Time To Say Goodbye, Hillary

Video: Hillary Clinton: Sniper Fire

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