Anybody who has ever stayed until quitting time at a gin mill knows the feeling. The crowd is thinning and the energy is sagging even before the bartender makes it official: Last call.

Barack Obama doesn't strike me as a guy who spends much time in saloons, but he's probably starting to get that last-call feeling. He has to know his presidential campaign is running out of time.

Sen. Hillary Clinton, she of the high negatives and polarizing personality, is pulling away from the Illinois rookie. Like water running downhill, she's filling all the cracks and crevices and leaving him no safe place to stand. The bigger her lead in the polls, the more gaffes he makes, which produces even bigger numbers for her. She has about a 20-point lead in national surveys, is now ahead in all the early states and has huge leads in delegate-rich Florida and California. Even Obama's wife, Michelle, is starting to show the strains, ominously warning an Iowa crowd that "the game of politics is to make you afraid, so that you don't think!"

Her point, presumably, was that voters should be afraid if her husband loses. Hmmm.

Time matters. We're only about four months from the first votes, and less when you realize the campaigns will be on holiday ice for much of December.

Clinton's big lead is a testament to her experience and her play-it-safe approach as well as to his careless mistakes on foreign policy. While she can't assume anything yet, she is building an advantage against the Republican pick. Rudy Giuliani and Mitt Romney are still forced to grovel before the archconservative wing of the GOP, while Clinton has the luxury of being able to tack toward the center. Indeed, one of the biggest surprises of the Democratic race is that Clinton is fending off the far-left challenges of Obama and former senator, and future lobbyist, John Edwards, without pandering in extremis.

Could it be that the wackadoo wing is growing up? Or are the adults taking over from the burn-the-house down radicals?

Either way, Clinton has benefited. When the campaign started, her 2002 pro-war vote had the potential to derail her. While it is still Obama's strong suit — he refers to it every time Iraq comes up — it clearly doesn't have the potency it did. It's almost as though voter anger has given way to cooler calculations about who is more ready to be president.

It's also true that Clinton has sometimes met the wackadoos halfway. Her vote against troop funding last May in the fight over Iraq timetables was a signal of her no-limits determination to win the nomination. It was, however, a serious mistake for anyone who wants to be commander in chief and will certainly be the focus of a GOP commercial in the general election.

But in general, she has also been more realistic about Iraq. Her recent comments that withdrawal could not be immediate and total struck the right balance, as have her plans to continue fighting al-Qaida. You'll know she is ready for the general election when she answers Giuliani's challenge and throws off the PC shackles to use the phrase "Islamic terrorists."

Obama needs to get the momentum back fast, but the problem is that debates have not helped. Clinton's gotten better at them and he's gotten worse. His only hope is to stay close and pull out at least two early state victories.

The one thing he can't count on is help from Clinton, who is less likely now to make big mistakes. Even the attacks from Karl Rove and Giuliani, designed to energize the GOP base, have strengthened her.

All of which adds up to Obama being alone at the bar. As bartenders have been known to say in such sad moments, you don't have to go home, but you can't stay here.

Michael Goodwin is a columnist for the New York Daily News. Reach him at mgoodwin@nydailynews.com.