In a blow to leftist Democrats, Texas congressional candidate Jessica Cisneros — who was endorsed by Rep. Alexandria Ocasio-Cortez, D-N.Y. — has lost in a recount for her party's nomination.

Incumbent Rep. Henry Cuellar, D-Texas, faced Justice Democrats-endorsed Cisneros in a tight runoff election that was too close to call for weeks, leading to a recount request from Cisneros, which concluded Tuesday that Cuellar not only won, but had a few more votes than initially reported.

"As I said on election night, ‘the margin will hold’ — and it has not only held but grown," Cuellar said in a statement Tuesday. The Texas Democratic Party's recount committee found that Cuellar won by 289 votes.

Cuellar said he appreciated the efforts of "election workers who sacrificed their time to once again confirm the voices of every voter across the 28th district were heard."

TEXAS DEM REP. CUELLAR INCREASES LEAD AGAINST JUSTICE DEMOCRAT-BACKED CANDIDATE WHO MAY SEEK RECOUNT

WASHINGTON, DC - JULY 30: U.S. Rep. Henry Cuellar (D-TX) speaks on southern border security and illegal immigration, during a news conference at the U.S. Capitol on July 30, 2021 in Washington, DC. Cuellar urged the Biden administration to name former Homeland Security Secretary Jeh Johnson as a border czar. (Photo by Kevin Dietsch/Getty Images)

U.S. Rep. Henry Cuellar (D-TX) speaks on southern border security and illegal immigration, during a news conference at the U.S. Capitol on July 30, 2021

"To those who did not vote for me, as your Congressman I will continue to work diligently for you in Washington. While we may differ on certain positions, we share a common ground on many issues to improve our communities and strengthen families," Cuellar said.

"We always knew this was an uphill battle," Cisneros said in a statement conceding to Cuellar. She blamed "a corrupt political machine, Republican-funded Super PACs, the Koch brothers, private prisons, Big Oil, the Chamber of Commerce, dark money groups, Big Pharma, and nearly the entire Democratic Party establishment in Washington" for opposing her.

She promised to continue organizing to elect more left-wing Democrats in Texas and said she would work toward supporting her party in the midterm elections in November. 

BERNIE SANDERS BACKS JESSICA CISNEROS AND HER PROMISES TO TEXAS' WORKING CLASS

"We’re going to keep fighting to create a more progressive and accountable Democratic Party this year and work to turn Texas blue in November," Cisneros said.

Democratic U.S. congressional candidate Jessica Cisneros (TX-28) concludes a speech alongside her family during a watch party on March 01, 2022 in Laredo, Texas. Late results hint that Cisneros and U.S. Rep. Henry Cuellar (D-TX) could face a primary runoff with neither getting more than the 50 percent necessary for an outright win

Democratic U.S. congressional candidate Jessica Cisneros (TX-28) concludes a speech alongside her family during a watch party on March 1, 2022 in Laredo, Texas. (Brandon Bell/Getty Images)

"We’re grateful to Jessica Cisneros for the positive campaign she ran — shining a light on the issues that are really impacting South Texas," Texas Democratic Party Chairman Gilberto Hinojosa said in a statement Tuesday. "We all know she will continue to fight for South Texans as we rally together behind our nominee, Henry Cuellar."

After the May 24 primary runoff election, Cuellar led Cisneros by 177 votes to secure the Democratic nomination and confidently asserted the margin would hold. Cisneros, however, declined at the time to concede the race.

Cuellar, who has served in Congress since 2005, congratulated Cisneros on "a hard-fought race" in a statement just before the certification of the runoff results. 

The runoff contest between Rep. Henry Cuellar and Democratic primary challenger Jessica Cisneros appears destined for a recount

Democrat Jessica Cisneros, who is campaigning for a House seat, meets her opponent U.S. Rep. Henry Cuellar (D-TX) for the first time during the campaign trail at the Citrus Parade in Mission, Texas, U.S. January 25, 2020. Picture taken Jan. 25, 2020. (REUTERS/Veronica Cardenas)

HOYER STANDS BY ENDORSEMENT OF PRO-LIFE CUELLAR AGAINST PROGRESSIVE PRIMARY OPPONENT, WHILE JEFFRIES DODGES

Cuellar is one of the last pro-life Democrats in the House and has been critical of the Biden administration's handling of the southern border crisis and rising inflation and promised to fight to protect oil and gas jobs and to lower taxes and the cost of health care.

Cisneros ran on a platform of progressive politics, promoting a pro-union message. 

The race between Cuellar and Cisneros gained more attention after a leaked Supreme Court opinion indicated Roe v. Wade could be overruled, placing abortion access up to state legislatures instead of having the practice protected by the judiciary as a constitutional right. 

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Cuellar will face Republican candidate Cassy Garcia in November as the GOP hopes to retake the majority in the House.