At one point, a moderator, Lester Holt, had to beckon Mr. Bloomberg to defend himself, observing that there was “a lot for you to respond to.”
“Um,” Mr. Bloomberg began. He said he was the best candidate to defeat President Trump and the leader with the experience to succeed if he did.
“I’m a mayor,” he said, “or was a mayor.” It had been a while.
Ms. Warren, straining to boost her chances after setbacks in the first two states, appeared particularly emboldened, tweaking Ms. Klobuchar on health care policy, Mr. Sanders for the vitriol among some of his supporters and, most gleefully, Mr. Bloomberg.
After a halting, if careful, answer from Mr. Bloomberg about the nondisclosure agreements — during which the former mayor recited various feats of gender parity in his business and government life — Ms. Warren challenged him to release women from the agreements if they wished to speak publicly about how they were treated in his employ.
“I hope you heard what his defense was,” Ms. Warren said, before paraphrasing liberally. “‘I’ve been nice to some women.’ That just doesn’t cut it.”
For much of the night, Mr. Bloomberg, who had not debated since his third and final mayoral election in 2009, looked both rusty and familiar. He was every bit the political patrician New Yorkers remember, referring to his fellow hopefuls as “my associates,” calling the debate a “panel” and joking that TurboTax would not suffice for the “thousands of pages” of financial documents he has yet to release.
He did appear to grow more confident later in the night, speaking forcefully on environmental issues and landing a well-practiced zinger or two.