There’s been a lot of talk lately about the coming battle over economic populism that could tear the Democratic Party apart. But it’s looking more and more like one side has already won.

Consider what happened this week: On Monday, Jon Cowan and Jim Kessler of Third Way, a centrist Democratic Washington think tank, published an op-ed in the Wall Street Journal that called an economic populist agenda “disastrous for Democrats.” It took particular exception to a proposal by Sen. Elizabeth Warren to expand Social Security, and blasted those who oppose cuts to Medicare. As its sole piece of evidence for the idea that populism is politically harmfu, it cited Colorado voters’ recent rejection of an initiative to raise taxes to pay for public education and universal pre-K.

Cowan and Kessler’s argument, on both the policy and the politics, has already been thoroughly demolished (see here and here, among other places). But what’s fascinating is the swift and decisive pushback their op-ed generated.

As the Huffington Post reported, Warren sent a letter to six big banks urigng them to dislcose the think tanks and lobby shops they fund—the implication being that much of the backing for groups advocating the kind of business-friendly economic poicies supported by Third Way comes, undisclosed. from Wall Street.

And a group of progressive Democratic organizations called on Rep. Allyson Schwartz, a Pennsylvania Democrat who’s running for governor, to drop her affiliation with Third Way, where she is listed as a “co-chair”. A spokesman for the congresswoman said she wouldn’t resign, but called the op-ed “outrageous,” and said Schwartz “strongly disagrees with it.”

It’s Schwartz’s response that’s most telling of all. Democrats running for office feel they simply can’t afford to be on the conservative side of this split.

There’s plenty of evidence that’s leading them to that view. But it’s striking nonetheless—and great news!—that a movement that not so long ago was embraced by a Democratic White House is now close to being purged from the party.