(Bloomberg) — Bernie Sanders and Elizabeth Warren dove into their dispute over whether a woman can win the 2020 presidential election, with Sanders flatly denying he ever said it was impossible. Warren was having none of it.”Look at the men on this stage — collectively, they have lost 10 elections,” Warren said in a Democratic presidential debate Tuesday in Iowa. “The only people on stage who have won every single election they’ve been in are the women.”The issue has strained a previously civil competition between Senators Sanders and Warren, who are fighting for the same progressive votes.Pressed for more details by debate moderators, Sanders and Warren set out to clear the record on their conflicting statements about a 2018 conversation in which Warren contends Sanders said a woman couldn’t beat President Donald Trump.“I didn’t say it,” Sanders said. “Anybody who know me knows that it’s incomprehensible to say that a woman could not be president of the United States.”Debating WarsEarlier, Sanders and Joe Biden confronted each other over the use of military force in the Middle East.Sanders called the Iraq war “the worst foreign policy blunder in modern American history” and attacked Biden for voting to authorize it. Biden said the vote in 2002 was a mistake but that as vice president under Barack Obama he would compare his record to anyone else’s.Sanders opposed the Iraq war but voted in favor of the war in Afghanistan. Biden said his Iraq war vote was a “big, big mistake” but that he later sought to prevent a surge in troops.From Iran to North Korea to nuclear proliferation, foreign policy dominated the first segment of the Des Moines Register/CNN debate as it hasn’t in six previous debates. The first question tested each candidate on their qualifications as commander-in-chief. That’s been a selling point for Biden, but his past foreign policy positions have come under new scrutiny — from the right and the left — for his support of the wars in Afghanistan and Iraq.The Democratic candidates have all opposed Trump’s decision to kill Iranian General Qassem Soleimani this month, saying it threatened to further destabilize the region.All the candidates argued for a diminished U.S. military role in the Middle East, but differed on how far they would go. Biden said there was a role for special forces working with allies, but Sanders and Senator Elizabeth Warren said they would pull out completely.“We should stop asking our military to solve problems that cannot be solved militarily,” Warren said.Former South Bend, Indiana Mayor Pete Buttigieg, a veteran of the Afghanistan war, said U.S. involvement should be limited, proposing that Congress should have to renew its authorization for military force every three years.Biden and Buttigieg are in a competitive four-way battle with Sanders and Warren for the campaign’s first contest: the Iowa caucuses on Feb. 3. Also participating in the debate were Senator Amy Klobuchar of Minnesota and billionaire investor Tom Steyer.While the Democratic primary started with the most diverse field of candidates in history, only white candidates made it to Tuesday’s debate stage. Cory Booker dropped out of the race on Monday while Andrew Yang, Tulsi Gabbard and Deval Patrick all missed the polling and fund-raising requirements to qualify for the January debate.Former New York Mayor Mike Bloomberg is self-funding his presidential campaign so he didn’t meet the donor requirement to participate. Bloomberg is the founder and majority owner of Bloomberg L.P., the parent company of Bloomberg News.Tuesday’s debate is the last such forum before the Iowa caucuses. It’s particularly important for the senators — Sanders, Warren and Klobuchar — who will have to break away from campaigning as soon as this week to be sworn in as jurors in Trump’s impeachment trial. After that, the trial could require their presence at the Capitol for weeks to come.To contact the reporters on this story: Gregory Korte in Washington at firstname.lastname@example.org;Misyrlena Egkolfopoulou in Washington at email@example.comTo contact the editors responsible for this story: Wendy Benjaminson at firstname.lastname@example.org, Larry Liebert, Magan CraneFor more articles like this, please visit us at bloomberg.com©2020 Bloomberg L.P.