WASHINGTON - There's nothing quite like a happy ending -- or at least what seems to pass for one.

Maybe that's why so many Democrats want to see a Barack Obama-Hillary Clinton ticket this fall.

The idea of a dream team is gaining ground again, now that Obama's close to locking up the nomination. The latest polls say about 60 per cent support it.

Some party luminaries are pushing it, including Mario Cuomo, the former governor of New York, and Pennsylvania Gov. Ed Rendell.

It would be an unbeatable union, say fans of the merger. An African-American and a woman, inspiration and experience, poetry and policy -- all in one package.

His popularity among blacks, the young and well-educated, affluent Americans would blend with Clinton's draw among women, seniors and average, white, male Joes.

It's a partnership that could reunite a party split along class and racial lines laid bare in an intense, bitter campaign.

"Why stop having a nominee who has the support of 51 per cent of Democrats when we could have a dream team ticket that has won 100 per cent?'' asks VoteBoth, a group backed by some prominent Clinton supporters that's urging people to sign an online petition.

But what are the chances it will actually happen?

"The odds are tiny,'' said Larry Sabato, a political analyst at the University of Virginia.

"A lot of this comes down to personal chemistry. It's not there,'' said Sabato.

"You can't rule it out entirely. It's always posssible the poohbahs in the Demcoratic party will insist on it.''

On that score, some are vehemently opposed.

Party icon Senator Ted Kennedy scorched the union by saying he hoped Obama would choose someone who's "in tune with his appeal for the nobler aspirations of the American people.''

"I think if we had real leadership -- as we do with Barack Obama -- in the number-two spot as well, it'd be enormously helpful.''

There's no question there's an enormous amount of antipathy between the two camps. One pundit has quipped that Obama would have to have his food checked if Clinton joined him in the White House.

After all, Clinton has spent the last few months portraying Obama as an inexperienced lightweight who can't be trusted to run the country and has a problem gettting whites to vote for him.

Obama, meantime, has pegged Clinton as part of the old school of divisive politics who will say anything to get elected.

Could they get past all that?

"These are professionals -- They know how to do this,'' said Allan Lichtman, a political historian and author at American University.

Bitter rivals can make successful allies, he argued, including John F. Kennedy and Lyndon Johnson in 1960.

Ronald Reagan also picked George H.W. Bush in 1980, after a tense campaign where Bush referred to his rival's policies as "vodoo economics.''

Would Clinton want the job?

"Why not?'' asks Lichtman, who argues it would keep her in the limelight and set her up for a run in 2012 if Obama loses to Republican John McCain this fall, as long as the party doesn't blame her.

She'd also be the heir apparent in 2016 if Obama served out two terms.

But presidential scholar Stephen Hess wonders why Obama would bother navigating the potential minefield that comes with Clinton and all her baggage.

"The first rule of picking a vice-president is do no harm. They make no difference anyway. Who actually votes for the vice-president?'' asks Hess, an adviser to several former presidents.

"There are a lot of perfectly acceptable candidates for him. It's not like he has to take her. And she brings Bill along. It's just plain awkward. There's no need to complicate things.''

Besides, said Hess, Obama doesn't need the New York senator, who's thrived in large states during the primaries, to beat McCain as he struggles to overcome the deep unpopularity of President George W. Bush.

"Could you really imagine a Democrat at this point losing New York or California?''

And Clinton, he argued, wouldn't help Obama capture the few states he'll likely lose because he's black.

"I don't see anything about Clinton that lessens that racial tension.''

Other analysts say the benefits of Clinton as a running mate are overstated.

Women who've flocked to her will line up behind Obama when the dust settles, they argue, despite their anger now about Clinton's thwarted hopes.

And while it may be the new conventional widsom of American politics that white working class voters carry the key to the presidency, politics professor Alan Abramowitz at Emory University doesn't buy it.

That segment of voters has been shrinking for decades, Abramowitz said in a recent analysis, while the number of professionals and managers has been rising.

Among Democratic voters, professionals and managers now outnumber labourers by about two to one.

"Someone should tell Hillary Clinton and Barack Obama about this and maybe the press too,'' said Abramowitz.

There are other choices with wide appeal for blue-collar workers, including former candidate John Edwards, a populist who gave Obama a big boost with his endorsement last week.

Still, Edwards, who ran for the nomination in 2004 and was John Kerry's vice-presidential pick, doesn't really fit into Obama's overriding message of change any more than Clinton.

There are a handful of others often cited as possibilities, including Senator Jim Webb of Virginia, who has military credentials as a Vietnam War veteran with a son who served in Iraq.

Ted Strickland, a former Ohio governor, was once a Methodist minister who could help Obama connect with religious voters. So could Virginia Gov. Tim Kaine, a former missionary.

Rendell is highly popular in the key battleground state of Pennsylvania and a Clinton supporter to boot.

And Senator Claire McCaskill from Missouri is a plain-talking former prosecutor who could bring her state into play for Obama.

Clinton has other disadvantages besides her troubled history with Bill in the White House and all the scandals they endured.

She'd provide instant ammunition for Republicans after telling voters that Obama would represent a "leap of faith'' and McCain is more qualified to be president. Bill once said Obama would be a "roll of the dice.''

But if the Obama-Clinton partnership actually did happen, said Lichtman, it would help sustain a lot of momentum for Democrats, who've attracted so many new voters during the primaries.

"What a wonderful message to have such an envelope-pushing ticket. It sends a signal that anyone can be part of the American dream.''