Sen. Elizabeth Warren (D-Mass.) elicited cheers from the crowd at the second Democratic primary debate on Tuesday when she pushed back on candidates who said progressive policies cannot be achieved.

"I don't understand why anybody goes to all the trouble of running for president of the United States just to talk about what we really can't do and shouldn't fight for," Warren said to loud applause from the Detroit crowd.

The comment was in response to former Rep. John Delaney (D-Md.), who said he was not running on "fairy tale" policies.

The exchange underscored a battle between centrists and progressives on the stage.

Delaney, a moderate who has lagged in the polls and fundraising, came out swinging against Warren and her fellow progressive Sen. Bernie Sanders (I-Vt.) on a number of issues, including health care.

"Why do we have to be the party of taking something away from people?" Delaney asked. "That's what they're running on. They're running on telling half the country that your health insurance is illegal."

Warren hit back at Delaney, accusing him of touting Republican talking points.

"We are the Democrats. We are not about taking health care from anyone. That's what the Republicans are trying to do, and we should stop using Republican talking points," she said.