With less than three weeks to go to the Iowa caucus, when Democrats begin to pick their candidate to take on Donald Trump in November’s presidential election, Tuesday’s debate in Des Moines was always going to be highly charged. In the end, a fiery clash between Elizabeth Warren and Bernie Sanders dominated the evening.

Only six candidates took to the stage for the debate – though six more hopefuls remain in the race, even after the departure of New Jersey senator Cory Booker from the contest this week.

Unsurprisingly, given the tensions with Iran since the US killing of senior general Qassem Suleimani, much of the debate focused on foreign policy. Former vice-president Joe Biden came under pressure, particularly from Bernie Sanders, for voting for the Iraq War, though Biden pointed out that he helped reduce US troop numbers in Iraq during the Obama administration.

Others argued that they had the characteristics to be an effective commander-in-chief – Warren by saying she would remove all US combat troops from the region. “We should stop asking our military to solve problems that cannot be solved militarily,” she said.

War veteran Pete Buttigieg recalled his own experience the day he said goodbye to family members and left for the Middle East.

But it was a clash over gender that was the standout moment of the debate. More than halfway through, the moderators asked Sanders about comments attributed to him in recent days which have cracked open his seemingly solid relationship with Warren – his colleague in the Senate and a fellow liberal.

According to reports, the Vermont senator told Warren in a 2018 meeting that he did not believe a woman could win the 2020 election. After calls by Sanders for Warren to publicly dismiss the reports, the Massachusetts senator instead said they were true.

‘Incomprehensible’

Sanders again denied making the comments during Tuesday’s debate, saying it was “incomprehensible” he would do so and noting that Hillary Clinton had won the popular vote in the 2016 presidential election. But Warren seized on the question, noting the role women candidates and voters had played in the Democrats’ victories in the 2018 midterm elections.

She also pointed to the electoral successes of the women on the stage. “Look at the men on this stage,” she said. “Collectively they have lost 10 elections. The only people on this stage who have won every single election that they’ve been in are the women. Amy and me” – a reference to Minnesota senator Amy Klobuchar.

Warren also said she was “the only person on this stage who has beaten an incumbent Republican any time in the past 30 years”, a comment that prompted a riposte from Sanders that he had beaten a Republican incumbent when he won his Vermont Senate seat. Warren said this had been 30 years ago, as her comment had indicated.

Warren also tackled the notion of electability, implicitly warning others about assumptions they make about Democratic voters. “The real danger we face as Democrats is picking a candidate who can’t pull our party together or someone who takes for granted big parts of the Democratic constituency.”

She referenced John F Kennedy and Barack Obama, noting that there was a time when people said that a Catholic or black American couldn’t win an election.

Standoff

As the debate ended, the tensions between Sanders and Warren appeared to continue. Sanders approached Warren and extended his hand, but she didn’t shake it. Instead a brief standoff seemed to ensue, caught by the cameras.

A clash between the two most progressive candidates in the race was in many ways inevitable. With both vying for the same voter space, there was always a need for one to break away, and articulate their distinctiveness.

How the night’s events will affect voters, however, is still unclear.

Three weeks before the Iowa caucus the race appears remarkably close, with the four top-performing candidates in polls – Biden, Sanders, Warren and Buttigieg – effectively splitting the vote.

A poll last week suggested that there is no real frontrunner in the Iowa caucus – only 40 per cent of registered voters have made up their minds, according to a Des Moines Register poll. The next three weeks will see a shift in dynamics, as senators Warren, Sanders and Klobuchar will be obliged to remain in Washington for the president’s impeachment trial.

This will give candidates like Biden, Buttigieg and Andrew Yang free rein in Iowa in the last weeks of campaigning. The question is whether they can capitalise on this advantage and win the all-important first primary contest.