Dan Janison Melville. N.Y. Tuesday January 26, 2010. Daniel Janison,

Dan Janison has been a reporter at Newsday since 1997.

Oh, what a show it could be.

Donald Trump would have a chance to call Hillary Clinton nasty names before a rapt TV audience ahead of the general election. Sen. Bernie Sanders could again criticize Clinton as a friend of Wall Street.

But Sanders also could explain why he calls Trump “a dangerous person” who slanders entire ethnic and religious groups, denies climate change, and favors the privileged.

Trump could trot out his “Crazy Bernie” taunt, dismiss his Senate career as the stuff of just another politician, make fun of “politically correct” Vermont hippies, or say anything that happened to cross his mind.

On the Jimmy Kimmel show Wednesday night, the presumptive Republican nominee clearly embraced the idea of a one-on-one debate with Sanders — who tweeted back: “Game on.”

But now it looks like much less of a sure thing.

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On Thursday, the real estate heir claimed he was joking — even though he had talked up the promotional value of such an event and said it would generate sky-high ratings.

Which allowed Sanders campaign manager Jeff Weaver to tell CNN: “We hope he [Trump] will not chicken out.” But that did appear to be the case.

Clearly Trump finds it useful at this point to magnify Sanders’ exposure in the belief that he won’t win the nomination but could sap Clinton.

But Trump might back off for strategic reasons, too.

This debate would be a unique, asymmetrical spectacle with an all-but-nominee of one party with the all-but-eliminated underdog of the other.

With little to lose, Sanders, if he wished, could even look like a Democratic uniter by defending Clinton against Trump-style personal needling.

Such a show could pose Sanders, who polls show with a net positive approval rating, against Trump, who polls show is viewed negatively by most voters, even more than Clinton.

Polls also show Sanders with a wider lead against Trump than Clinton’s in a fantasy league matchup.

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A Sanders-Trump debate also would put side by side the two big surprises of the season — Trump for having captured a nomination and Sanders for having battled this long against a candidate who was expected to own the Democratic field.

Maybe Sanders and Trump would even debate the comparative virtues of big-government socialism versus corporate capitalism.

For local audiences, Trump, 69, could reminisce about once working at his father’s real-estate entity on Avenue Z in Brooklyn while Sanders, 74, recalled his own younger days living three miles away near Avenue P.

They could even chat about why they haven’t released their no-doubt-radically-different tax filings.

All this would no doubt further secure the 2016 campaign’s special place in the annals of performance art.