Of all the Democrats looking for openings in the party’s presidential debate in Las Vegas, perhaps none was looking harder than the man not on the stage.

Vice President Joe Biden has been struggling for months now — in public and in private — with whether to mount a run. Many in the party have been growing impatient with his indecision. And if there was a loser Tuesday night, it might have been him. Because it sure didn’t seem like any doors of opportunity opened for him at the debate.

If Biden wants in, he’s going to have to bang the door down himself.

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In a debate with tons of substance, well-articulated points of view and no cheap shots or demeaning comments — in other words, not a Republican debate — it is not clear there is a crying need for Biden to enter the race, unless and until the polls show little improvement in Clinton's standing among the general electorate. What would he add?

Much of that impression stems from the performances of the two front-runners, former Secretary of State Hillary Rodham Clinton and Sen. Bernie Sanders of Vermont.

Clinton was sure-footed and quick all night and easily gave as much as she got. She seemed comfortable in her own skin and as relaxed as she ever has been.

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Sanders exuded passion, authenticity and anger at Wall Street and big money everywhere in calling for a political revolution — without coming off as a crazy old man.

And together, they combined to put Clinton’s continuing email problem to rest — at least until her testimony next week before the House Benghazi committee. Based on her responses in Las Vegas, that should be great theater.

The most memorable moment of the night was Sanders railing that Americans are “sick and tired of hearing about your damn emails.” And Clinton reaching over with a smile to shake his hand while the audience gave them a standing ovation.

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That moment also was reflective of the entire debate in illuminating Biden’s problem. This field — add former Maryland Gov. Martin O’Malley and, if you must, the outmatched Jim Webb and hopeless Lincoln Chafee — came off as adults dealing with real problems, channeling the pain felt by everyday Americans, and willing to work together to get results.

Whether any of them moved the needle of public opinion remains to be seen. This is politics, of course, and things can change quickly, but it’s hard to imagine the debate is going to have the elites of the Democratic Party (never mind regular voters) waking up Wednesday morning and making a fevered pitch to Biden to save them.

The Draft Biden super PAC trying to convince the veep to get into the race released another television commercial hours before the debate. This one was titled “Never Quit.”

He won’t have to, if he never gets in.

Michael Dobie is a member of the Newsday editorial board.