LIVE OAK, Texas — A revolution may be brewing in South Texas, where Henry Cuellar — one of the most conservative Democrats in Congress — faces a young immigration lawyer backed by a who’s who from the party’s left wing, including presidential front-runner Sen. Bernie Sanders and Rep. Alexandria Ocasio-Cortez of New York.

Millions in outside spending have poured in as abortion-rights groups, unions and progressive groups pitch in for the 26-year-old challenger, Jessica Cisneros.

The incumbent, a 64-year-old pro-gun, pro-trade centrist who hasn’t had a serious challenge since winning the seat 15 years ago, is getting help from one of the most peculiar alliances in memory, a team that includes Speaker Nancy Pelosi and the party’s House campaign arm and, startlingly, the donor network created by the ultra-conservative Koch brothers.

“It’s unbelievable the amount of money being spent on the campaign,” said Laredo Mayor Pete Saenz.

Progressives tout Cisneros as the next Ocasio-Cortez, the former bartender who toppled one of Pelosi’s top lieutenants, Joe Crowley, in 2018. Cisneros enjoys backing from Justice Democrats, the same group that propelled Ocasio-Cortez.

Cuellar’s national profile isn’t as high as Crowley’s was, so an upset in Texas’ March 3 primary wouldn’t rock the party establishment quite as much, though it would affirm the growing clout of a left wing impatient with old school deal-making moderates.

Pelosi will be in Laredo on Saturday to raise money for Cuellar, leaving no doubt that she hasn’t budged from her embrace last fall at the Texas Tribune Festival when she declared that she “absolutely, absolutely, absolutely, absolutely” supports him, despite the fact that only one other House Democrat votes more often with President Donald Trump.

In one of the most remarkable turns in a Texas race in decades, Cuellar collected an endorsement last week from the Libre Initiative, a donor network backed by the conservative Koch brothers — Charles and his late brother David — that had never endorsed a Democrat for Congress.

“It’s just about the most damning thing that could happen to Cuellar. He is now a Koch-funded Democrat,” said Ezra Levin, co-founder and co-executive director of the Indivisible Project, a progressive group. “I don’t see how anybody can look at that endorsement and investment from this reactionary conservative force in American politics, in this safe Democratic seat, and say, OK, that’s the Democrat we want.”

The Cuellar campaign did not respond to multiple requests for comments on the Koch backing and other aspects of the campaign.

“He’s panicking,” Cisneros said.

“I’m sure they’re doing it for different reasons. The speaker sees that it’s her role to protect incumbents and protect the majority.” As for the Koch network, she said, “the fact that they decided to weigh in, knowing that they are readily identified as far right, is because they’re scared that Cuellar actually is going to lose this race.”

“I think that bodes well,” she said.

Saenz, the Laredo mayor and one of a long list of local officials who supports the incumbent, lauds Cuellar’s role in promoting trade, the local airport and relations with Mexico.

“I know what he can produce and what he brings to our city,” he said. “He’s a great asset to Laredo and I would hate to lose him.”

Congressional candidate Jessica Cisneros leaves a flyer at a home in Live Oak, Texas, on Feb. 19, 2020, as she campaigns to unseat Rep. Henry Cuellar, D-Laredo, in the March 3 Democratic primary. (Todd J. Gillman / staff)

Congressional candidate Jessica Cisneros checks for the next home on her list as she campaigns in Live Oak, Texas, on Feb. 19, 2020. (Todd J. Gillman / staff)

Vast and overwhelmingly Democratic district

It’s an overwhelmingly Democratic district the size of New Jersey, over 300 miles end to end from Mission in the Rio Grande Valley to Laredo, then north into the San Antonio suburbs.

Trump lost here by 20 percentage points.

In Live Oak, northeast of San Antonio, Cisneros spent a recent afternoon knocking on doors in a bucolic neighborhood of single family homes, with little luck. Most had video doorbells, and even residents who were home shooed her away without opening the door.

She was not discouraged, tucking a signed campaign mailer into the door handle or mail slot.

The Texas Organizing Project, one of the progressive groups working to help her unseat Cuellar, had already canvassed the area, as evidenced by pro-Cisneros and pro-Sanders mailers tucked under doormats.

Julián Castro added his endorsement recently. The former Housing secretary and presidential contender served as mayor of San Antonio, and Cisneros needs to run up the score in Bexar County, far from the incumbent’s base in Laredo, where Cuellar’s brother is Webb County sheriff and their sister is the county tax assessor-collector.

One attack ad from Cuellar boasts that while he “stands with families,” she “supports allowing minors to have an abortion without parents’ knowledge,” an inflammatory attack aimed at riling socially conservative Latino voters.

Cuellar also accuses her of moving into the district only six months ago.

Not true, says Cisneros, who says she’s lived in Laredo all her life except for a 9-month fellowship learning about New York City’s public defender system. Even during college and law school at the University of Texas, she says, she spent weekends in Laredo thanks to her dad, a trucker who would swing by on Fridays and return her to Austin on Sundays as he plied the Interstate 35 route.

Given that it’s such a safe seat, Cuellar’s rare level of bipartisanship has long rankled liberals.

President George W. Bush embraced Rep. Henry Cuellar, a Laredo Democrat, at his 2006 State of the Union address. (Rich Lipski / The Washington Post)

As a state House member in 2000, he stumped for Gov. George W. Bush’s presidential bid. Bush’s successor, Rick Perry, appointed him secretary of state — the state’s top election official and emissary on Mexico and border issues.

He ran for Congress in 2002 against a GOP incumbent. In 2004, he turned his sights on a fellow Democrat, four-term Rep. Ciro Rodriguez, a reliable liberal from San Antonio who chaired the Congressional Hispanic Caucus at the time.

Cuellar beat him by 203 votes, fended him off easily in a rematch, and has coasted to reelection ever since, often unopposed in the primary.

At the 2006 State of the Union speech, Cuellar sat on the GOP side of the House, where Bush spotted him — cupping his face with both hands in a gesture of affection that incensed many Democrats.

During the Obama era, fellow Democrats and Hispanic caucus members found new reasons to seethe as Cuellar teamed up with Sen. John Cornyn, then the Senate’s deputy GOP leader, on a bill to speed deportation of Central American children, and with Austin Rep. Michael McCaul, then chairman of Homeland Security, on border issues.

Cuellar pushed for more focus on enforcement than some Democrats were comfortable with, while also demanding a path to citizenship and other elements of their immigration agenda.

Few Democrats side with Republicans as often, but it’s a nuanced picture.

In Trump’s first two years, Cuellar voted with the president 69% of the time, according to records compiled by FiveThirtyEight, though that plummeted to 10% in the past year.

He has defied Trump on major issues, opposing funds for a border wall, for instance, and voting to open the impeachment inquiry and then to formally impeach Trump on counts of abuse of power and obstruction of Congress.

He waited until the final hours before announcing his support for impeachment, however, insisting he was taking a measured, lawyerly approach and seeking as much evidence as possible before making his call on such a weighty issue. That opened him to attack by Cisneros.

Earlier this month, he was one of just seven House Democrats to oppose an effort to rewrite labor laws and strengthen unions, a key Democratic bloc.

It’s a record that invites mistrust from some, and plaudits from others.

“Cuellar has been a model of what an effective congressman should look like. On issues ranging from immigration to trade to jobs and the economy, our congressman has been a consensus builder,” Daniel Garza, senior adviser to the Libre Initiative Action — the arm of the Koch brothers network that endorsed him on Friday — wrote in a memo explaining the support.

Cuellar’s campaign spokesman, Colin Strother, told the Laredo Morning Times in December that the congressman “understands the district and has a proven record of getting things done. .... Liberal senators in Massachusetts and Hollywood actresses might be supporting her campaign, but nobody in the district is."

Strange bedfellows

Outside groups have poured at least $2.3 million into the 28th district, making the race one of the costliest and most closely watched in Texas.

Texas Forward, a super PAC affiliated with EMILY’s List, which supports women who support abortion rights, has spent at least $1.2 million on ads to help Cisneros, including one that asserts there’s a “damn big difference” between her and an incumbent who “says” he’s a Democrat but voted to cut funding for Planned Parenthood and opposed raising the minimum wage.

The Texas Organizing Project, Communications Workers of America, the Service Employees International Union and other groups vowed Monday to put at least $350,000 behind Cisneros for ads, phone banking and the like.

In Cuellar’s corner, the U.S. Chamber of Commerce, which rarely backs Democrats, launched a $200,000 campaign focused on his support for the U.S.-Mexico-Canada Agreement, Trump’s much-touted upgrade to the North American Free Trade Agreement.

Some $330 billion in goods and services crossed the border at Laredo last year, making it the No. 1 land port in the Americas.

Other conservative groups are also pitching in. A mysterious, newly formed nonprofit that has not disclosed its donors called American Workers for Progress has reported $720,000 to praise Cuellar’s record on health care. The American Banking Association is spending $60,000 on radio spots.

After spending $2.3 million defending his seat so far, Cuellar still had $2 million in the bank as of Feb. 12, thanks to cash reserves stockpiled through the years. Cisneros has spent $1 million and is down to $300,000 for the final push.

She’s backed by the Texas AFL-CIO, MoveOn, NARAL Pro-Choice America, Planned Parenthood Action Fund, the Working Families Party, the League of Conservation Voters, Sen. Elizabeth Warren, and two other progressive stars who serve with Cuellar in Congress, Reps. Pramila Jayapal of Washington state and Ayanna Pressley of Massachusetts.

Cisneros keeps some distance from Ocasio-Cortez and the socialist label, though.

“I obviously admire her a lot and appreciate all the support she’s giving the campaign,” she said, but “in South Texas we all tend to shy away from labels. We don’t like to be placed in a box.”