DES MOINES, Iowa (AP) — The Democratic Party’s leading presidential candidates sparred over Iraq, war and foreign policy Tuesday night in the final debate showdown before primary voting begins.

Progressive Sen. Bernie Sanders drew an immediate contrast with establishment favorite Joe Biden by noting that Sanders aggressively fought against a 2002 measure to authorize military action against Iraq.

Sanders called the Iraqi invasion “the worst foreign policy blunder in the modern history of this country.”

Biden acknowledged that his 2002 vote was “a mistake,” but highlighted his role in the Obama administration helping to draw down the U.S. military presence in the region.

Just six candidates gathered in Des Moines, each eager to seize a dose of final-days momentum on national television before Iowa’s Feb. 3 caucuses. It was not the focus in the debate’s earliest moments, but a sudden “he-said, she-said” dispute over gender involving two longtime allies, Bernie Sanders and Elizabeth Warren, loomed over the event.

Specifically, Warren charged publicly on the eve of the debate that Sanders told her during a private 2018 meeting that he didn’t think a woman could defeat Trump, a claim tinged with sexism that Sanders vigorously denied. Amid an immediate uproar on the left, there were signs that both candidates wanted to deescalate the situation.

The feuding was likely to expand to include nearly every candidate on stage by night’s end.

Sanders has recently stepped up his attacks on Biden over his past support of the Iraq War, broad free-trade agreements and entitlement reform, among other issues. Minnesota Sen. Amy Klobuchar, who has had several strong debates, will be looking for another opportunity as she remains mired in the middle of the pack in polling. Billionaire Tom Steyer will have to answer criticism that he’s trying to buy his way to the White House.

And with two surveys showing Pete Buttigieg losing support in Iowa, the former mayor of South Bend, Indiana, will need a breakout moment to regain strength before the caucuses.

Trump, campaigning in neighboring Wisconsin just as Democrats took the debate stage, tried to encourage the feud between Sanders and Warren from afar.

“She said that Bernie stated strongly that a woman can’t win. I don’t believe that Bernie said that, I really don’t. It’s not the kind of thing Bernie would say,” Trump said.

Peoples and Superville reported from Washington. Associated Press writers Bill Barrow in Des Moines contributed to this report.