Former Austin City Council member Greg Casar handily won the Democratic primary for an open seat in Texas’ 35th Congressional District on Tuesday while progressive immigration attorney Jessica Cisneros forced Rep. Henry Cuellar—a corporate-funded Democrat under FBI investigation—into a runoff contest in the state’s 28th district.

“Our campaign has built a movement of working people, from San Antonio to Austin, who are ready to fight.”

Casar, a democratic socialist endorsed by Rep. Alexandria Ocasio-Cortez (D-N.Y.) and Sen. Bernie Sanders (I-Vt.), had over 61% of the vote after results were tallied in more than 95% of precincts in the 35th district, which stretches from East Austin into San Antonio. The district is a Democratic stronghold, meaning Casar’s primary victory likely secures him a seat in Congress.

“Our campaign has built a movement of working people, from San Antonio to Austin, who are ready to fight because our futures depend on it,” Casar said in a statement declaring victory Tuesday night. “I’m incredibly honored to be the next Democratic nominee for TX-35.”

“Together,” Casar added, “we’re taking our fight to the halls of Congress—to fight and deliver on passing Medicare for All, protecting reproductive rights, creating good jobs, and fixing our power grid.”

Cisneros, meanwhile, is headed to a runoff election with Cuellar after neither candidate received more than 50% of the vote, the threshold needed to win outright. The runoff will take place in May.

The progressive attorney led the closely watched primary rematch much of the night, but Cuellar—an anti-abortion Democrat supported by House Majority Leader Steny Hoyer (D-Md.)—pulled slightly ahead as results from typically more conservative counties rolled in. As of this writing, Cuellar has 48.5% of the vote while Cisneros has 46.8%.

“We don’t let that hope die, because we know we deserve so much better.”

One of the most corporate-friendly Democrats in Congress, Cuellar has been a major obstacle to the passage of President Joe Biden’s domestic policy agenda and has repeatedly hit the president from the right on immigration.

One election analyst argued that “the key to Cuellar living to fight another day” is “pro-Trump Dem primary voters along the border who responded to his anti-progressive messaging.”

Addressing her supporters late Tuesday, Cisneros presented her grassroots campaign as a challenge to a powerful machine that elects lawmakers who “don’t respond to our communities’ needs.”

“We’re showing that our dreams can compete neck-and-neck, and we’re gonna show that we’re going to come out on top,” said Cisneros. “We don’t let that hope die, because we know we deserve so much better.”

Varshini Prakash, executive director of the youth-led Sunrise Movement, said in a statement early Wednesday that Casar’s victory and Cisneros’ strong showing are powerful testaments to the popularity of the Green New Deal, a policy vision that both candidates touted during their campaigns.

“We are thrilled that Greg Casar won his race today,” said Prakash. “Greg is an organizer like us who ran on a Green New Deal, on a Green New Grid, and who was on the frontlines of his community when the Texas Freeze hit.”

“The reality is Jessica’s race was always going to be an uphill battle,” Prakash added, “but it’s clear Texans are sick of Cuellar’s corruption and obstruction of climate legislation in Congress. We’re immensely proud of what we did and the progress we made: we knocked on thousands of doors and made over 700,000 contacts to voters, and proved that young people will come out for progressive candidates. This is the power of people over money. Jessica ran an incredible campaign that we’ve been grateful to be a part of. We’re behind Jessica and we will fight with her to see this through.”