On a crowded stage in Detroit, 2020 Democratic candidates Sen. Bernie Sanders (D-Vt.) and Sen. Elizabeth Warren (D-Mass.) stood shoulder to shoulder on Tuesday evening to defend their left-leaning social programs in a debate that brought a stream of challenges from the other eight, more moderate, Democrats.

At issue were several progressive proposals, including Sanders’s “Medicare for All” bill, which aims to replace all private healthcare plans with government-sponsored Medicare, as well as Warren’s proposed college-tuition forgiveness program, which would write down or forgive outstanding student-loan debt for millions of college graduates. Warren has also come out in favor of decriminalizing border crossings by undocumented migrants.

Former Congressman John Delaney from Maryland challenged Sanders directly, saying that Medicare for All was both impractical and undesirable for 150 million or more Americans who already have a private healthcare plan they like.

Delaney was perhaps the most outspoken, as he criticized far-left policies held by both Sanders and Warren. He warned the debate panel that these policies would not sit well with voters and would be very likely to get President Trump re-elected.

Rep. Tim Ryan of Ohio tended to agree with Delaney. He accused Sanders of not fully grasping the effects that Medicare for All bill would have on union workers, an accusation to which Sanders replied by yelling, “I do know. I wrote the damn bill!”

Mayor of South Bend, Indiana, Pete Buttigieg served as a calm voice of reason at times, advocating for Democrats to put aside their differences and seek unity. “It’s time we stop worrying about what the Republicans will say,” he said. Buttigieg also spoke strongly on the need to respond to the threats posed by climate change, seeking to put in place a plan for Americans to no longer use fossil fuels by 2030.

Minnesota Senator Amy Klobuchar seemed to gain a little ground in Tuesday evening’s debate. She was given a several-minute private interview by CNN after the debate finished, and she appears to be one of the candidates the Democrats would like to see continue on to the next round of debates in Houston.

The ten remaining Democratic candidates will now take the stage on Wednesday evening, including front-runner Joe Biden and Sen. Kamala Harris (D-Calif.), who sparred with one another on the subject of racism during late-June’s debate in Miami.