We voters are a forgiving sort. We give out second chances freely, willing to overlook extramarital affairs, tawdry scandals and the lies that tried to cover them up. We put great faith in the wonders of time, atonement and, of course, therapy for righting political leaders' previous wrongs.

But third chances are something altogether different, and that's exactly what Anthony Weiner asked for Tuesday. Following revelations on a gossip news site that he had continued "sexting" with another woman as late as last summer, Weiner held a news conference on Tuesday where he again apologized for his lewd behavior, which this time occurred not only after he resigned from Congress, but after he had sat for a photo in a July 2012 People magazine article where his wife said he was "trying to be the best dad and husband he can be."

"I want to bring my vision to the people of the city of New York," he said on Tuesday. "I hope they're willing to continue to still give me a second chance."

But New Yorkers have already done that. It doesn't matter that he warned at the start of his campaign that more tawdry details would come out, or that he has apologized for his actions. He failed their trust. A man who apologized and seemed to be taking steps toward redemption went back and did it all over again—and brazenly so, under the reported pseudonym "Carlos Danger."

This may be, as Weiner's wife, Huma Abedin, said in front of the news cameras Tuesday, an issue that's "between us and our marriage." But it's also an issue between someone who wants to be New York City's chief executive and the city residents he would lead. It raises serious questions about his powers of self-control, his judgment and the hubris with which he sees his mayoral bid.

People are willing to forgive and forget if leaders can prove they've changed their ways and that the offense won't happen again. But that willingness to forgive rests on a shaky bridge of rebuilt trust that can crumble under repeat transgressions. For Weiner, the damage to it may now be beyond repair.

Jena McGregor is a columnist for On Leadership.

Read also:

Anthony Weiner vs. Carlos Danger: The politics of the post-paramour era

David Petraeus, Mark Sanford, Anthony Weiner and the art of the comeback

GALLERY: Scandal-plagued pols - Where are they now? 

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