Next week’s Democratic primary in Texas’ 7th District is no longer a race about who gets to challenge the Republican incumbent in a traditionally conservative Houston-area district. Houston’s west side is now the site of this year’s first full-blown proxy war between the Bernie Sanders wing of the Democratic Party and its far more moderate establishment.

On Thursday, Our Revolution, an outside group formed from the remains of Sanders’ 2016 campaign, endorsed Laura Moser, a progressive, first-time candidate hoping to challenge Republican Rep. John Culberson. The endorsement came one week after Moser found herself under attack from the Democratic Congressional Campaign Committee. Our Revolution made no secret that it was that not-so-friendly fire by the official campaign arm of House Democrats that helped convince the group to get involved in the primary. “The people of Texas should be allowed to make their own decisions on who to vote for without the influence of Washington insiders,” Our Revolution board member Jim Hightower said in a statement, which also highlighted Moser’s support for Sanders-style progressive planks like raising the minimum wage and Medicare for all. (Hightower happens to be the state’s former agriculture commissioner and one of the last Democrats to win statewide office.)

The intra-party tension in the seven-way race has been simmering for a while, but it boiled over into the public late last week when the DCCC dumped its opposition research file on Moser. Moser is a former freelance journalist who created Daily Action, a text-message service that provides users with one specific task each day they can do to “resist the Trump agenda,” and has written for a number of national outlets, including Slate. Last summer, after she had already began campaigning, she wrote critically of Rep. Ben Ray Luján (D-New Mexico), the chairman of the DCCC, after he promised that the group wouldn’t use support for abortion rights as a litmus test.

The DCCC was careful to limit its public critique to Moser’s personal story, not her progressive policy agenda, but it’s clear the group felt she was too far left to win in a general election. While the Democratic group has not publicly backed one of the other candidates in the race, some like-minded allies like EMILY’s List have lined up behind Lizzie Pannill Fletcher, a Houston-area attorney.

“Democratic voters need to hear that Laura Moser is not going to change Washington,” the DCCC memo said. “She is a Washington insider, who begrudgingly moved to Houston to run for Congress.” The oppo file went on to list four bullet points, the first three of which highlighted the fact that Moser previously lived in D.C. and the last of which criticized Moser for hiring her husband’s D.C. consulting firm to work on her campaign.

It’s unclear that the DCCC’s broadside hit its mark, though. One of the attacks—that a joke about living in rural Texas should disqualify you from running for office in Houston—suggested it was the DCCC, not Moser, who was out of touch with the district. The DCCC’s intervention also turned out to be a financial boon for Moser, who had already proved adept at using social media to raise her profile—and money—outside of Texas. According to her campaign, Moser raised more than $100,000 in the six days following the DCCC attack, a significant slice of which the campaign proudly trumpeted came from small donors outside of her district. The endorsement from Our Revolution is likely to keep the national small-donor spigot running. (Bernie Sanders is no longer technically involved in the group’s decision-making, but Our Revolution shares a name with the book he published shortly after the 2016 presidential election and is stocked with a number of his allies, including his former chief of staff in the Senate. For his part, Bernie has been more judicious with his endorsement and is currently only personally backing three House candidates, one each in Iowa, Wisconsin, and Illinois.)

The question, of course, is whether all that outside help will translate at the polls. If none of the candidates crack the 50-percent threshold in next Tuesday’s primary—a real possibility given the crowded field—the top two vote-getters would then proceed to a runoff. Whoever the nominee turns out to be will face off against Culberson in a district that has been represented by Republicans for the past half-century, but which went for Hillary Clinton in 2016. The midterm results should shed light on how far and how fast Texas is moving left. But well before that happens, the results of the primary may just tell us the same thing about the Democratic Party.