Tim Walz and J.D. Vance took victory laps after locking horns in their US vice presidential debate, with the civil tone of the televised clash largely absent back on the campaign trail.

Vance, who has earned a reputation as an aggressive, bombastic defender of Republican presidential nominee Donald Trump, surprised pundits with a cordial, policy-focused performance in Tuesday's CBS News debate in New York.

But he was back in his "Trump's pitbull" persona as he mocked verbal gaffes made by his opponent, while Walz used his own post-debate rally to assail Vance over comments on democracy that were considered the Ohio Republican's weakest moment.

Vance, 40, had been challenged by Walz to name the winner of the 2020 election, which Trump falsely claims was stolen from him.

He declined to acknowledge that his boss was in the wrong.

"The moment that really stuck out is, I just asked the simplest of all questions that every single American should be able to answer. I asked him if Donald Trump lost the 2020 election. He refused to answer," Walz, 60, told a crowd in York, Pennsylvania.

Tuesday's showdown, shared among 15 US networks, attracted an estimated domestic audience of 43 million viewers, a drop from the 58 million who saw Kamala Harris take on Mike Pence in 2020 when he was the vice president and she was the challenger.

Harris replaced Pence in the last election and is now vying for the top job against Trump. The rivals' presidential debate last month was watched by 67 million viewers in America.

Walz, the governor of Minnesota, called Tuesday's clash as "spirited" but described Vance as a "slick talker" who had got away with several false claims on Trump's record in office.

'Disqualifying'

Walz likened Vance's refusal to acknowledge Trump's 2020 defeat to the VP hopeful's recent assertion that he would not have refused to help his running made overturn the results, as Pence did.

"Understand in that 88th minute last night, with that damning non-answer, Senator Vance made it clear: he will always make a different choice than Mike Pence made," Walz said.

"And as I said then and I will say now, that should be absolutely disqualifying if you're asking to be the vice president."

Vance -- who has been credited with a strong debate performance, although snap polls made the clash a virtual tie -- did not address the 2020 election during remarks in Michigan focused mostly on attacking Harris over inflation.

But he was asked about it during a post-speech Q&A and accused the media of being "obsessed" with 2020.

"I'm focused on the election of 33 days from now because I want to throw Kamala Harris out of office and get back to commonsense economic policies," Vance said.

He mocked Walz for saying he was friends with school shooters -- Walz is presumed to have meant he was friends with the victims -- calling it "probably only the third or fourth dumbest comment Tim Walz made that night."

"I've got to be honest, I feel a little bad for Governor Walz," Vance told his audience at an aeropace supplier in Auburn Hills.

"And the reason I feel bad for him is because he has to defend the indefensible, and that is the record of Kamala Harris."

© Agence France-Presse By Frankie TAGGART