The third Democratic debate on Thursday was billed as the first showdown between the top contenders: Vice President Joe Biden, Sen. Elizabeth Warren and Sen. Bernie Sanders.

Biden did challenge the liberal senators on health care early in the debate, which was broadcast on ABC. He asked repeatedly how they would pay for their multi-trillion dollar Medicare for All plan, saying that Warren’s wealth tax left the proposal $28 trillion short. When Sanders pointed out that other countries, including Canada, pay half of what America does per capita on health care.

“This is America,” Biden shot back.

But for the most part, the debate belonged to the lower-tier candidates. Candidates like Sen. Amy Klobuchar and former Rep. Beto O’Rourke, who had gotten lost in the crowd in the previous debates, got an opportunity to shine with the field winnowed from 20 to 10. Klobuchar and Mayor Pete Buttigieg presented themselves as moderate alternatives who could take on Sanders and Warren should Biden stumble.

The ABC moderators largely allowed the candidates to speak, not imposing brief time limits as at the earlier debate. The candidates were able to give full answers on Afghanistan, student loan debt, immigration, and race.

As with the earlier debates, the first 30 minutes dealt with health care. Biden, Klobuchar, O’Rourke and Buttigieg defended a more incremental approach to getting to universal health care, offering a contrast with the Medicare for All supporters.

Buttigieg, who supports “Medicare for all who want it,” told Sanders that the problem with his proposal was that it “does not trust the American people.”

“I trust the American people to make the best choice for them,” he said to Sanders. “Why don’t you?”

Julian Castro, the former housing secretary, challenged Biden on the issue, saying that Biden’s plan would leave 10 million people uninsured. He also made a veiled swipe at Biden’s age, saying that Biden was “forgetting what you said two minutes ago.”

“I’m fulfilling the legacy of Barack Obama and you’re not,” Castro said.

“That would be a surprise to him,” Biden shot back.

Klobuchar also went after Sanders on health care, saying that ending private insurance is “not a bold idea. I think it’s a bad idea.”

Sen. Kamala Harris, who challenged Biden in the first debate, mostly the focus on President Trump. In her opening statement, she addressed the president directly, saying the only reason he had not been indicted was because of the Department of Justice policy against prosecuting a sitting president. “What you don’t get is that the American people are so much better than this and we know that the vast majority of us have so much more in common than what separates us,” she said.

Sen. Cory Booker called on Democrats to temper their differences, and not “sacrifice progress on the altar of purity.”

“We have one shot to make Donald Trump a one-term president,” he said. “We cannot lose it by the way we talk to each other.”

O’Rourke, who faltered badly in the first debate, found his stride when the subject turned to gun violence. O’Rourke argued that the El Paso shooting, in which 22 people were killed by a white supremacist at a Wal-mart, represented an inflection point in the country’s approach to the issue. O’Rourke gave an unapologetic defense of a mandatory buyback of assault weapons, saying they were designed to kill on the battlefield and are now being used against children.

“Hell yes we’re going to take your AR-15, your AK-47,” he said, to raucous applause. “We’re not going to allow it to be used against our fellow Americans anymore.”

Jorge Ramos, the Univision anchor, pressed Biden on the Obama Administration’s record on immigration, asking if it was a mistake to ramp up deportations. Biden defended Obama’s record, even when challenged again by Castro.

“I stand with Barack Obama — all eight years, good, bad, and indifferent,” Biden said.