When is it time for a public official to resign? The scandal that erupted over the last 10 days involving Rep. Anthony Weiner (D-N.Y.) — his string of denials followed by a reversal at a surreal press conference on Monday — should have Americans considering just how low their expectations for public servants have fallen.

Give Rep. Weiner some credit. Unlike other politicians who have blamed personal peccadilloes on illnesses or addictions, Weiner didn’t offer any such excuse at his press conference. I had expected Weiner to claim a sexual addiction, and ask the press to leave him to his rehabilitation. Given the circumstances — some of these sexting "relationships" went back three years, and involved at least a half-dozen women — that excuse might have worked to generate at least a little sympathy. Weiner eschewed that, specifically denying that addictions had anything to do with his behavior.

Nor did Weiner haul his wife in front of the cameras to deflect some of the vitriol of the press. Reporters repeatedly asked the disgraced congressman whether he and Huma Abedin would separate. Weiner told her earlier in the day that the allegations were all true, and told the press that she was "very unhappy" with him, but that the two would work out their problems together. Without explicitly saying so, Weiner suggested that he didn't bring her to the press conference because the shame belonged to him alone, a rather refreshing change from other disgraced politicians who keep their families on stage as shields against the press in these confessional moments.

Had Weiner acted honestly from the start, much of what happened on Monday would have been avoided. After all, as Weiner noted repeatedly during the press conference, he had done nothing illegal in conducting sexual conversations online. To his knowledge, those conversations were with other adult women, and there's no evidence that inappropriate conversations ever took place with minors, a question specifically asked at the presser. He claimed his actions did not break rules or ethics standards in the House of Representatives, although House Minority Leader Nancy Pelosi is taking no chances, calling for a House Ethics Committee probe to be sure Weiner’s actions didn’t involve House resources or break any rules.  

Lying in an attempt to evade responsibility marks Weiner as eminently untrustworthy, not just in a marital sense, but also as a public servant.

A week ago, Weiner could have addressed the media by admitting to the inappropriate social-networking behavior, apologizing to his wife and his supporters, and promising to learn his lesson and end all such contacts in the future. He would have looked foolish, immature, and perhaps even somewhat predatory and creepy. But the story would have ended in hours, and remained as nothing more than a political punchline. The national media would happily have turned their attention elsewhere, with any further disclosures disarmed by a full admission.

Instead, Weiner lied. He lied all week. He allowed his associates to attack the media for asking questions about a story that clearly did not add up. Weiner even allowed his staff to call the police on a well-known TV reporter from his city simply for wanting to ask Weiner more questions. In the end, Weiner still looks immature, foolish, creepy – and now he looks like a liar as well.

Reporters at the press conference demanded to know whether Weiner would resign, and he said categorically that he would remain in his office. His fellow former New York congressman, Republican Chris Lee, resigned under similar circumstances after sending a shirtless picture to a Craigslist acquaintance in search of a date, which is a big no-no for married men even in Washington, D.C. But resignations don’t always follow from sex scandals in Congress — not even among Republicans, as some of my conservative friends seem to believe, and not even when laws are broken. Sen. Larry Craig refused to resign after his arrest and guilty plea for importuning an undercover police officer in a Minneapolis airport restroom came to light, retiring instead at the end of his term. David Vitter is still in the Senate, years after his connection to a prostitution ring in Washington was uncovered.

Weiner, however, might be a different case. Lee admitted his guilt almost immediately, and Vitter did as well. Craig insisted that he didn’t try to ask a police officer for sex, infamously claiming that he took a "wide stance" in the bathroom stall, but didn’t deny that he had been arrested, or that he had pled guilty to the charge.  

Weiner went on interview after interview to deny that he had sent the tweet, blaming hackers and pranksters, and then scolded the press for wasting time asking him about the scandal. Weiner, who cultivated a following as a familiar talking head on cable shows, now has a very large credibility problem. When he speaks, who will believe him? What media source will allow any assertions by the congressman to stand on their own? Being a foolish, immature creep is one thing, but lying in an attempt to evade responsibility marks Weiner as eminently untrustworthy, not just in a marital sense, but also as a public servant.

It's almost certainly true that Weiner didn't break any laws by engaging in his extracurricular social-media tomcattery. It's equally true that Weiner has made it clear that he will lie to get himself out of trouble until the moment when lies don’t work any longer, and only then tearfully admitting what everyone else knew despite his attempts to cover up the truth. The former means that Weiner doesn't have to resign, but the latter means he probably should. In another age, we would say that Weiner brought shame and disgrace on his office, even if he did nothing prosecutable, and that the honorable action would be to resign. Since Weiner can't bring himself to act honorably in this case, it falls to the voters in his district to see whether they care to demand a standard of honor at all when Weiner runs for re-election in 2012.