Joe Biden warned donors Tuesday that his presidential rivals’ support for Medicare for All could hurt Democratic candidates for other offices in 2020.

“I’ve heard and you’ve heard too from an awful lot of Democrats who are running for the Senate, the House and governors, they think that if we go with some of the other more interesting plans that have been put forward, that they may not be able to win their elections,” Biden said during a video-conference fundraiser.

Biden, who entered the Democratic race as the front-runner, is under increasing pressure in polls from Elizabeth Warren, who advocates a government-run health care system that abolishes private insurance. Biden favors building on the existing system by adding a public option to Obamacare.

House Speaker Nancy Pelosi told Bloomberg reporters and editors last week that she was worried such proposals could damage Democrats in 2020, winning over liberal enclaves but losing electoral college must-win states in the industrial Midwest.

Biden seemed to agree. “Go out and ask your Democratic members of the House and Senate in your districts and ask them whether or not they support Medicare for All, whether they think they can win on that and where they’re going to find $34 trillion in 10 years to do it,” he said. The cost estimate he cited reflected a Medicare for All proposal from Bernie Sanders. Warren says it will cost $20.5 trillion

Biden has said his plan would be a significant step toward universal health care that would’ve been perceived as “radical” just a few years ago.

“Look, the plan I put forward on health care is radical by standards of four years ago or five years ago and it will get everyone covered. And it’s going to cost 1/30th of what the plan for Medicare for All will,” he said.

This article was provided by Bloomberg News.