If there was a ringleader for this cranky band of defeatists, it was former Rep. John Delaney (D-Md.), who spent much of his time in Congress deregulating big banks and much of his stage time Tuesday attacking “Medicare for All,” a Green New Deal and a wealth tax on the richest Americans.

Throughout Tuesday night’s debate, the self-styled moderates repeatedly took aim at the two most popular candidates on stage ― Sens. Elizabeth Warren (D-Mass.) and Bernie Sanders (I-Vt.) ― insisting their policy ideas were “unrealistic,” “radical” and unpopular.

“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.”

After 90 minutes, Warren seemed to have had enough. When Delaney attacked Warren for “fairy-tale economics,” Warren delivered the most devastating line of the night.

WARREN ethers Delaney: "I don't understand why anybody goes to all the trouble of running for president of the United States to talk about what we really can't do and shouldn't fight for." pic.twitter.com/ymDj6ggsve

For a brief moment, Delaney’s Wikipedia bio was edited to state that he was killed in the exchange. (This was a joke. Delaney survived ― barely.)

It’s hard to pass laws that change the country for the better. But much of what the moderate candidates on stage were arguing ― Delaney, along with former Colorado Gov. John Hickenlooper, Montana Gov. Steve Bullock and Rep. Tim Ryan (D-Ohio) ― simply wasn’t any more realistic than what the more unapologetic progressives were pitching.

Senate Majority Leader Mitch McConnell (R-Ky.) blocked every piece of President Barack Obama’s agenda he could. He refused to even hold a hearing on Obama’s Supreme Court nominee Merrick Garland. Republicans are not likely to reward Democrats with votes if Democrats pre-emptively tone down their ambition. They’re going to oppose the agenda of any Democratic president, just as they opposed the agenda of the last Democratic president, a moderate.

You could see this delusion clearly in Delaney’s attack on Warren’s wealth tax. He claimed he agreed with Warren about the need to raise taxes on the rich but insisted that raising the capital gains tax ― the tax on stocks, bonds and financial investments ― was a more “realistic solution” than applying a new wealth tax targeting the very rich.

In 2017, Republicans passed more than $1 trillion in tax cuts overwhelmingly devoted to the rich. Every Republican in Congress has signed a pledge to never raise taxes, ever. They aren’t going to support a tax hike on rich people in any form.

Warren and Sanders are betting that a bolder agenda will get more popular support than a tepid one, and they’re hoping to leverage this popularity against Republicans. They might be right and they might be wrong. But Medicare for All and a Green New Deal are no less realistic than claiming McConnell will reach across the aisle to raise taxes on millionaires if you just do it the right way. The hard part isn’t the agenda, it’s the votes in the Senate and on the Supreme Court.

“We beat [Republicans] by being the party of big structural change,” Warren said. “We can’t choose a candidate we don’t believe in just because we’re too scared to do anything else. And we can’t ask other people to vote for a candidate we don’t believe in. Democrats win when we figure out what is right and we get out there and fight for it.”

Warren’s wealth tax would apply to people with a personal net worth of at least $50 million. Delaney, a former financial services executive, has a net worth of $65 million.