Sen. Elizabeth Warren and Bernie Sanders sparred on Tuesday night over the question of electability, as Sanders denied having said that a woman could not win the presidency.

Warren said on Monday that Sanders had told her in December 2018 that a woman could not be elected — while Sanders said the claim was “ludicrous.” While both candidates said on Tuesday night that they did not want to engage in personal attacks, the conflict did allow each to make a pitch for their own ability to defeat President Trump.

“Does anybody in their right mind think a woman cannot be elected president? Nobody believes that,” Sanders asked. “The real question is how do we beat Trump.”

He argued that the grassroots energy behind his campaign makes him best positioned for November.

Warren cautioned against glossing over the issue, and argued that the two female candidates on stage had won every election they’d contested, while the four men had lost 10 elections combined.

“Since Donald Trump was elected, women candidates have outperformed men candidates in competitive races,” Warren said. “Look, don’t deny that the question is there. Back in the 1960s, people asked ‘Could a Catholic win?’ Back in 2008, people asked if an African-American could win. And both times the Democratic Party stepped up and said yes… That is who we are.”

Earlier, Sanders squared off with former vice president Joe Biden over the issue of trade. Sanders said he had voted against NAFTA and normalizing trade relations with China, and said that such agreements were written for one reason: “to increase the profits of large multi-national corporations.”

Biden defended trade agreements in general, saying it is possible to write international rules that protect workers.

“So we better figure out how we begin to write the rules of the road, not China,” Biden said.

Sanders has also been turning up the heat on Biden leading into the debate, attacking him on his support for Social Security cuts and the Iraq war.

Former mayor Pete Buttigieg and Sen. Amy Klobuchar argued late in the debate that they are electable because they hail from the Midwest — the key region Democrats need to win back against Trump.

“I am from the exact kind of industrial community he pretends to speak to but has turned his back on,” Buttigieg said.

Biden said he would relish having an economic debate with Trump, arguing that working class and middle class people are in “real trouble.”

“They’re being clobbered now, being killed, and now have a situation where the vast majority believe their children will never reach the stage that they’ve reached in economic security,” he said.

Biden also argued that he has already proven that he can withstand Trump’s attacks.

“I’ve been the object of his affection now more than anybody else on the stage,” Biden said. “I’ve taken all the hits he can deliver, and I’m getting better in the polls.”