Anthony Weiner was back in his old form, displaying flashes of sharp intelligence and odd quirks of personality as he returned to the campaign circuit Tuesday.

At turns sarcastic and amiable, patronizing and principled, the disgraced lawmaker-turned-New York City mayoral candidate took the stage at New York University for his first debate since he resigned from Congress in scandal in June 2011.

Weiner has refused to bow to his critics, who want to write off the career of a man once seen as the leading contender to replace Mayor Michael Bloomberg over the revelation that the married man had tweeted racy images of himself to other women.

Instead, he put pride and embarrassment aside, faced his past and threw his hat back in the ring. 

It may prove to have been worth the risk, as the nearly two years since Weiner left Washington appears to be a political lifetime ago for many city voters. Especially if a new Marist poll that has him in second place among Democratic nominees in the race -- just five points behind City Council Speaker Christine Quinn -- is to be believed.

But it's not so simple, as the survey has him losing to Quinn by 15 points in the likely event of a runoff if none of the six Democratic  primary candidates garners 40 percent of the vote in September.

Still, Weiner was warmly received at a Tuesday forum on education hosted by New Yorkers for Great Public Schools, particularly by members of the press who tripped over one another for a photo or quip from the politician.

Meanwhile, Quinn was booed in absentia, as she decided not to attend the debate, even though event organizers reportedly changed the date three times to fit her schedule.

It could just be that Weiner's got more time on his hands ever since he was brought down by his sexting scandal. Still the day was a huge success for Weiner -- who signed on to participate in the debate on Monday as Quinn pulled out at the last minute -- and another blow to Quinn's candidacy, which was already reeling from the new poll numbers.

It brought to mind a question central to Weiner's chances, and to his very candidacy, namely: Can this man actually win?

He had a real connection with voters present for the packed-house debate, and his intelligence shined through at times, sharp as ever.

Yet the other side of Weiner was still there, seemingly undiminished, maybe even reinforced. He was the only candidate not to wear a suit jacket. He was the only one who chose to stand when replying to questions he liked. He was the only one to distractedly lay his microphone on the table and rest his chin on his hands for extended portions of the debate.

He has said he wants voters to give him "a second chance," but at NYU Tuesday he seemed like a caricature of the old Weiner, with both his best and worst qualities exacerbated by time and silence. Many voters will see the familiar dismissive sneer on TV and reflect on all that would likely come along with electing Weiner.

Another camp says that he's gone rogue. Against the wishes of many fellow Democrats, Weiner will be back on the ballot come Primary Day, and he's doing it his way this time around.

After weeks of testing the waters and internally polling on his potential candidacy, Weiner jumped back into the ring last week, and he's immediately become a major player in the 2013 mayoral race.

Either New York voters have short memories (unlikely in the lurid case of Weiner's demise), or they simply don't care enough about Weiner's social media failings to write him off. But he still has to overcome the fact that he lied to the voting public as he tried to spin away the scandal. Perhaps more potentially damning is the real possibility that other women will come forward with incriminating Weiner tales or photos. He admits he "can't say" if such bombshells may emerge.

Despite everything he has going against him, Weiner is coming out swinging, and at Tuesday's debate he struck back at Gov. Andrew Cuomo, who insulted him last week by saying "shame on us" if New Yorkers elect Weiner to fill Bloomberg's shoes.

"I may have to fight with Gov. Cuomo on some things. Honestly he started it," he said, drawing laughs from the crowd with one of several characteristic barbs and jokes he lobbed during the event.

Plus he's got the second-biggest campaign chest, with about $5 million (much of which is left over from previous campaigns) to spend on the race.

Weiner is resurgent, taking the offensive in the early stages of a wide-open campaign season, but he's got a long road ahead if he's going to be -- as he repeatedly said Tuesday -- "lucky enough to get" New Yorkers to suppress their misgivings and send him to City Hall.

The takeaway: Weiner's all in, and he and his past are his biggest obstacles. The race is on.