Volkswagen workers in Chattanooga, Tennessee, have overwhelmingly voted to join the United Auto Workers — marking a major milestone for the union and its first successful organizing drive of an automaker outside of Detroit’s Big Three.

Union organizing passed with 73% of the vote, or 2,628 workers, in support for the UAW, according to the National Labor Relations Board, which oversaw the election. A total of roughly 3,620, or about 84%, of the 4,326 eligible VW workers voted in the election, the NLRB said. Seven ballots were challenged and three others were voided.

“In a historic victory, an overwhelming majority of Volkswagen workers in Chattanooga, Tennessee, have voted to join the UAW,” the union said in a release Friday night before official results were released by the NLRB. “While votes continue to be tallied, the outcome is clear: Volkswagen workers in Chattanooga are the first Southern autoworkers outside of the Big Three to win their union.”

The NLRB still must certify the result, but barring any unexpected issues or challenges, the company is required to bargain in good faith with the union. The talks can be direct or go first through a mediator.

The sides have five business days to file objections to the election, according to the NLRB. If no objections are filed, the result will be certified.

VW confirmed the UAW’s win in a release Friday night but offered little additional comment.

“We will await certification of the results by the NLRB,” the company said. “Volkswagen thanks its Chattanooga workers for voting in this election.”

UAW leaders and supporters are expected to use the win as a launching point for the union’s unprecedented organizing campaign of 13 automakers in the U.S. following major contract wins last year with General Motors, Ford Motor and Chrysler parent Stellantis.

President Joe Biden, who has heavily supported organized labor and the UAW, congratulated the union on its “historic vote.”

“Across the country, union members have logged major wins and large raises, including auto workers, actors, port workers, Teamsters, writers, warehouse and health care workers, and more. Together, these union wins have helped raise wages and demonstrate once again that the middle-class built America and that unions are still building and expanding the middle class for all workers,” Biden said in a statement.

UAW President Shawn Fain and others saw this week’s vote as the union’s best shot at organizing the VW plant following the strikes and record contracts at the Detroit automakers. Those agreements included significant wage increase, reinstatement of cost-of-living adjustments and other benefits.

The successful organizing drive comes days after six Republican governors of Southern states, including Tennessee Gov. Bill Lee, released a joint statement condemning the UAW’s push to organize in their states.

“We have worked tirelessly on behalf of our constituents to bring good-paying jobs to our states. These jobs have become part of the fabric of the automotive manufacturing industry. Unionization would certainly put our states’ jobs in jeopardy — in fact, in this year already, all of the UAW automakers have announced layoffs,” the statement said.

The UAW previously failed to organize the Volkswagen plant in 2014 and 2019 as it faced greater outside political pressure and worker opposition. Workers rejected union membership by just 833 to 776 votes five years ago.

The union will now set its sights on negotiating with VW. It will also look to an anticipated organizing vote of Mercedes-Benz workers at an SUV plant in Vance, Alabama.

Workers at the facility earlier this month filed NLRB paperwork for a formal election to join the UAW. The vote for 5,200 workers will occur from May 13 through May 17, the NLRB announced Thursday.

“The first thing you need to do to win is to believe that you can win,” Fain told Mercedes-Benz workers last month. “That this job can be better. That your life can be better. And that those things are worth fighting for. That is why we stand up. That’s why you’re here today. Because deep down, you believe it’s possible.”

Fain previously vowed to move beyond the Big Three and expand to the “Big Five or Big Six” by the time its four-and-a-half-year contracts with the Detroit automakers expire in 2028.