Sen. Elizabeth Warren drew repeated fire from her competitors in the Democrats’ 4th presidential debate Tuesday night, while Joe Biden faded to the background for long stretches, underscoring how much the primary campaign has shifted.

For the most part, Warren, who came into the debate tied with or slightly leading Biden in polls, kept her cool and avoided firing back at any of the candidates on stage. That was amidst accusations she was being evasive on the cost and consequences of her Medicare for All health-care plan, of being a Washington insider out of touch with Rust Belt voters, and of being a candidate whose slate of progressive ideas could sink the party in 2020.

In doing so, some — like Mayor Pete Buttigieg, of South Bend, Ind., and Sen. Amy Klobuchar of Minnesota also presented themselves as relatively moderate alternatives to Biden — should the former vice president fade.

Buttigieg and Klobuchar are the only two candidates from the Midwest and have touted their ability to appeal to independents, moderates, and Democrats who voted for Donald Trump in 2016.

On Tuesday, both came out strongly against polices that are more progressive and could be tough to enact — and tougher to pitch to moderate voters. Both pushed back on former Texas Rep. Beto O’Rourke’s call for mandatory buybacks of assault-style rifles.

After O’Rourke called out Buttigieg for dismissing the idea “a shiny object,” and a slap in the face to survivors, Buttigieg said he was being practical. “What we owe those survivors is to actually deliver a solution.”

While Biden absorbed the most bruising attacks in past debates, Warren and her ideas dominated the first hour of the debate in Ohio, with trailing candidates trying to score points by knocking them down.

Polling shows most Democrats favor holding onto a private option for health-care coverage, something that Warren’s plan would not allow. She got hammered on that point and others, even though Medicare for All is Vermont Sen. Bernie Sanders’ “damn bill,” as he called it.

She continued to dodge on whether middle-class taxes would rise, instead insisting the total cost for these voters would go down.

“This is why people in the middle class are so frustrated with Washington in general,” Buttigeig said. “Your signature, Senator, is to have a plan for everything — except this.”

Klobuchar was more caustic. “At least Sen. Sanders is honest," she said, noting he has admitted taxes would rise. “We need to be honest here and tell the American people where we’re going to send the invoice.”

As her challengers took swipes, Warren stayed on message, arguing that big structural change is possible, if Democrats fight for it. She used the Consumer Financial Protection Bureau, which she helped create, as evidence of that. “It was dream big, fight hard," she said. "People told me go for something little. ... I said no.”

Biden sticks to the script on Ukraine

Biden, pushed to respond to the accusations that Trump has thrown at him and his son, stuck to his script.

“My son did nothing wrong. I did nothing wrong. I carried out the policy of the United States government in rooting out corruption in Ukraine. And that's what we should be focusing on,” Biden said in his most high-profile response yet to the attacks that have threatened his candidacy.

While fact-checkers have debunked the Trump attack that Biden acted in self-interest when he pushed for the removal of a Ukrainian prosecutor (who was known to be soft on corruption), the former vice president still faces questions about why his son had landed a high-paying job on the board of a gas company in a country entangled with U.S. foreign policy.

Biden added little to his past defenses but attempted to turn the fight back to Trump, saying the focus should be on the president’s “corruption.”

The controversy came up quickly in the first hour, and by 9:30 there was no further mention of it — showing that Democrats are loath to repeat Trump’s attacks, even if it might help them take down a rival, and, perhaps, that few now see attacking Biden as a priority.

He has been a target before, but Tuesday night, the field was content to let him linger in the background. That could be the most worrying sign for him.

Sanders shows heart

Sanders’ heart attack was, of course, a question he faced in his first national appearance since the 78-year-old’s medical scare two weeks ago. Along with using his answer to promote a rally in Queens, N.Y., the senator also showed a rarer trait for him: emotion.

The typically cantankerous Sanders solemnly thanked his rivals and others “from all over this country” for their “love, for their prayers, for their well wishes, and I just want to thank you from the bottom of my heart, and I’m so happy to be back here with you this evening.”

The moment drew applause from all his rivals, creating a rare moment of genuine emotional warmth, both for Sanders and, for that matter, for any political debate.

Later, however, Sanders was back to his combative self. After Biden hit his liberal rivals by saying he was the only person on stage “who has ever gotten anything big done,” Sanders fired back: “I say this as a friend, but you got the Iraq war done.”

Democrats unite on impeachment

While past debates have opened with 30 minutes or so of sharp disputes on health care, Tuesday night’s started with one of the few things that unifies nearly all Democrats: impeaching Donald Trump.

Every one made the case for why their party is investigating a potential impeachment, creating an opening sequence that displayed Democratic unity against what they see as a fundamentally dangerous presidency.

In doing so, they for once used a debate opening to show a sense of unified purpose rather than diving into a dispute over whether they should push policy leftward, or really far leftward. And while health care is the top policy concern for many Democratic voters, many of them would settle for simply ending Trump’s presidency.

“Sometimes there are issues that are bigger than politics, and I think that’s the case with this impeachment inquiry,” Warren said, setting the stage with the first answer of the night. “We took a constitutional oath, and that is that no one is above the law, and that includes the president of the United States.”

Sanders followed up by adding to the case, saying Trump “is enriching himself while using the Oval Office to do that, and that is outrageous.”

Each Democrat came at the issue with a different flavor — “I know a confession when I see one,” said California Sen. Kamala Harris, a former prosecutor, while New Jersey Sen. Cory Booker said, “We have to conduct this process in a way that is honorable, that brings our country together” — but overall it amounted to a lengthy opening statement from would-be Democratic prosecutors, all before a national audience.

While many focused on Trump’s action, Buttigieg, in a very on-brand way, also looked to the future, asking viewers to imagine the day after Trump leaves office — and casting this as a fight for the future.

“A president 10 years or 100 years from now will look back at this moment and draw the conclusion either that no one is above the law or that a president can get away with anything,” Buttigieg said.

After that initial exchange, though, Trump was barely mentioned for the rest of the night. The candidates seemed more intent on tackling one another, casting aside one central thing the party agrees on. It might not matter, though: Trump dominates the discussion, and many voters already have firm, and fixed, opinions, on him. No debate will change that.