For the senators running for president, Tuesday’s debate carried extra importance.

It wasn’t just the last debate ahead of the state’s caucuses — just three weeks away — it was also potentially their last big hoorah in the Hawkeye State before they’re stuck in Washington for the Senate impeachment trial of President Donald Trump that’s set to begin next week.

“Some things are more important than politics,” Massachusetts Sen. Elizabeth Warren said when asked whether she was concerned the impending impeachment trial would keep her off the trail. She quickly pivoted to how impeachment underscores one of her messages: corruption. 

“We need to draw that distinction and show that as Democrats, we are not going to be the people who are just out for the big corporations, people who want to help themselves,” Warren said.

The CNN and Des Moines Register moderators only posed that question directly to Warren, but the compressed timeframe was no doubt part of the calculus of Sens. Bernie Sanders of Vermont and Amy Klobuchar of Minnesota on Tuesday night too. (Colorado Sen. Michael Bennet, the only other senator left in the race after New Jersey Sen. Cory Booker dropped out on Monday, did not qualify for Tuesday’s debate.)

They’ll all be hard-pressed to get back to  Iowa much before the Feb. 3 caucuses. The House is voting on sending the articles of impeachment to the Senate today, and Majority Leader Mitch McConnell has indicated the trial will begin on Tuesday — the day after Martin Luther King Jr. Day. The trial is expected to run six days a week.

The senators occupied half the debate stage — the smallest one so far and the first one since Trump ordered the killing of an influential Iranian commander. The setting gave them a platform to tout their congressional experience and expose their differences

Can a woman win?

Heading into Tuesday night, all eyes were on Sanders and Warren to see whether simmering tensions would bubble up on stage before they retreat to the more staid corridors of the Senate next week.

The campaigns’ last-minute squabbling began with a Politico report over the weekend of a Sanders campaign script for volunteers that criticized Warren. On the eve of the debate, CNN reported on a 2018 private meeting where Sanders reportedly told Warren a woman couldn’t win the presidency.

Sanders on Tuesday night continued to deny that account, which Warren had previously verified in a Monday statement.

“Anybody who knows me knows that it’s incomprehensible that I would think that a woman could not be president of the United States,” Sanders said, adding that he held back on launching his 2016 campaign until Warren — whose supporters were trying to draft her — took a pass. 

Warren again said she “disagreed” with Sanders’ alleged doubts about a woman’s electoral viability, but she stole the moment when she pointed out the winning records of the men and women on stage.

“So, can a woman beat Donald Trump? Look at the men on this stage. Collectively, they have lost 10 elections,” Warren said. “The only people on this stage who have won every single election that they’ve been in are the women, Amy and me,” she said. Both Warren and Klobuchar won their first elections as underdogs. 

After an awkward moment when Sanders challenged Warren’s assessment of his electoral history, the two-term Massachusetts senator again pointed to the success of women — this time highlighting the role female candidates, voters and donors played in the 2018 midterms.

The midwestern senator

No senator had more riding on Tuesday’s debate than Klobuchar. If Sanders, Biden, Warren and former South Bend Mayor Peter Buttigieg are tied in Iowa, she’s firmly in the second tier and needed a strong performance to sustain and grow an energy in the state.

The three-term senator has made electability her biggest pitch, arguing that the Democratic nominee should be someone who has won in the Midwest. That was a frequent refrain again Tuesday night.

When Warren and Sanders were disagreeing over the the U.S.-Mexico-Canada trade agreement (Warren supports it; Sanders does not), Klobuchar swept in with one of her characteristic attempts at straight-talking: “Brianne, I want to hit reality here,” she told Des Moines Register reporter Brianne Pfannenstiel. 

“Thank you for bringing up Iowa, Brianne, since that is where we are,” Klobuchar said, before talking about a plant she visited in the state where workers lost their jobs.

Klobuchar didn’t hesitate to interrupt her colleagues and single out areas where she’s distinguished herself — either in the Senate or with plans on her campaign website. She said she was the only senator on stage who posed questions to both the secretaries of Defense and State at the intelligence briefing senators received last week about Iran. 

Running as a moderate opposed to “Medicare for All,” Klobuchar seized on emerging fault lines between Sanders and Warren on healthcare to back up her pitch for a public option. 

“This debate isn’t real,” Klobuchar said about “Medicare for All.” 

“The real debate we should be having is how do we make it easier for people to get coverage for addiction and mental health. I have a plan for that,” Klobuchar said, adopting a line that’s become a tagline of Warren’s. 

She again cut into Warren later when talking about education. “I appreciate your thoughts Elizabeth, but I want to step back,” Klobuchar said.

“Some of our colleagues who want free college for all aren’t actually thinking big enough,” Klobuchar said. “We are not going to have a shortage of MBAs, we are going to have a shortage of plumbers,” she added, again trying to appeal to the blue-collar voters in the Midwest she’s arguing will side with her — not Warren or Sanders — in a general election against Trump. 

“I’m going to be here any moment that I can,” she said, when asked after the debate how she’d keep up a presence in Iowa during the Senate impeachment trial.

Klobuchar told CNN that she has her husband and daughter and a roster of local surrogates to help.

But that may not be enough.

“This is going to get more intense every day, particularly for those senators back in Washington,” former Obama campaign manager David Plouffe said on MSNBC after the debate.

“They’re exercising their constitutional duty, when Pete Buttigieg and Joe Biden are talking to thousands of Iowans who are deciding,” he added.