The New York Working Families Party, a major force in the states progressive politics, voted Saturday to endorse Cynthia Nixon in New Yorks Democratic gubernatorial primary.

Nixon, an actress and longtime education activist, received 91.5 percent of the vote at a meeting of the party committee in Albany.

I am indebted to you today and every day, because you are the heart and the soul of the progressive New York that we want to create a New York that belongs to all of us, Nixon said in a speech accepting the endorsement.

The move is a blow to New York Gov. Andrew Cuomo that sets the stage for one of the highest-stakes Democratic primaries since the 2016 contest between former Secretary of State Hillary Clinton and Sen. Bernie Sanders (I-Vt.). Nixons left-wing challenge to Cuomo, which has thus far been considered a long shot, now has one of the most sought-after liberal endorsements in the state.

The New York Working Families Party, which labor unions and community groups formed two decades ago as a progressive faction within the Democratic Party , also voted to endorse New York City Councilman Jumaane Williams for lieutenant governor. Williams is challenging incumbent Lt. Gov. Kathy Hochul (D).

Cuomo has sought to unite progressive groups and labor unions behind his bid for a third term. Three major unions backing Cuomo Service Employees International Union Local 32BJ, the Communications Workers of America District 1 and the Teamsters Joint Council 16 withdrew from the Working Families Party on Friday on the eve of the expected vote for Nixon.

Bill Lipton, director of the New York Working Families Party, claimed that the governor threatened to cut off contact with unions that back groups that have endorsed Nixon. Labor leaders at odds with the WFP have vehemently denied this version of events.

Theres no truth to what Bill Lipton is saying this is nothing more than a diversionary tactic, said Stuart Appelbaum, president of the Retail, Wholesale and Department Store Union. Labor is leaving the party we started because Bill Lipton is using it for his own personal agenda.

Cuomos campaign dismissed the significance of the Working Families Partys blessing of Nixon, given the withdrawal of several of the labor unions that helped found it.

The governor stands with the unions who have left the WFP and no longer feel it represents the interests of middle- and working-class New Yorkers, said Abby Fashouer, a Cuomo re-election campaign spokeswoman.