Anthony Weiner, confessed liar, vowed yesterday to keep his congressional seat. He insists that he will stay. He should go.The six-term Democrat wants us to believe that his behavior was merely “a deep personal failing.” But it was far worse than that. A member of Congress is a public servant whose credibility hinges on whether the public deems him trustworthy. Trust was the currency in Weiner’s pocket, and he spent it all. He sent lewd photos of himself to women he didn’t know, “sexting” at least six of them (almost as if he was begging to be caught), and then, when hit with the first hint of exposure, he lied about it for 10 consecutive days – only to come clean yesterday, with the ritual tears of apologia, not because he suddenly had an epiphany that candor was the right thing to do, but only because ABC News, working with conservative hit man Andrew Breitbart (vindicated, if only in this case), had the goods on him.What’s the point of this guy staying on the job? Who’s going to listen to him?The past doesn’t offer much guidance on how best to assess what Weiner should do next. Some politicians have quit their jobs in the wake of their sex scandals (actual sex, virtual sex, flirtations, etc.), but others have not. Their decisions did not fall along partisan lines. Here’s a quick alphabetic rundown – although, given the volume of miscreants since the late ’90s, I have surely forgotten somebody.Quit: John Ensign, Mark Foley, Christopher Lee, Eric Massa, Jim McGreevey, Eliot Spitzer, Mark Souder.Stayed: Bill Clinton, Larry Craig, Vito Fossella, Mark Sanford, David Vitter.(Arnold Schwarzenegger wasn’t outed until after he left his gubernatorial job. John Edwards, at the time of his exposure, was long gone from the Senate.)It looks as if Weiner is going for the Vito Fossella model. Fossella, you may recall, was the Republican congressman who had a wife and three kids on Staten Island, and a mistress and daughter in Virginia. His double life was outed in May 2008 when he was busted on a DUI rap in Virginia. Like Weiner today, Fossella was in the midst of his sixth term. He refused to quit. Even though his naughtiness went far beyond the virtual, he served out the remainder of his term, choosing not to run for re-election in 2008. But Weiner shouldn’t even bother to take it that far. He has made himself expendable. His most distinguished achievement, as a congressman, has been his ubiquity on the cable TV shout fests, playing the part of the talking-point liberal warrior. That’s gone now. He can’t show up in the studio to assail the Republicans about wanting to privatize Medicare, because the folks at home would be thinking about his crotch, and the multiple lies he told. He would be trying to convey the Democratic message, and instead they would be wondering about the immaturity of a grown man who felt the narcissistic need to transmit his virtual groin to strangers. Meanwhile, his long-gestating bid for the New York mayoralty is dead. The tabloids would eat him alive if he pursued the job in 2013. The lewd photos are bad enough; the footage of his lies will follow him forever. Besides, the House Democrats don’t need Weiner; they can run another candidate in his solidly Democratic district (parts of Brooklyn and Queens), and win handily without him. House Democratic leader Nancy Pelosi is obviously trying to send him a message, by announcing that the House Ethics Committee should determine whether he broke any chamber rules – that’s akin to her saying, “If you stay, we’ll keep a cloud over your head” – but she need not be coy. She should just tell him to go, the same way John Boehner in 2010 prevailed upon Mark Souder to quit. Weiner’s credibility is shot, and he’s a lousy role model for the kids in his district who probably spend too much time online already. All told, the Democrats want to focus on the 2012 races, and the Weiner distraction is a luxury they can ill afford to indulge.