The United Auto Workers’ overwhelming election victory at a Volkswagen plant in Tennessee is giving the union hope that it can make broader inroads in the South, the least unionized part of the country.

The UAW won a stunning 73% of the vote at VW after losing elections in 2014 and 2019. It was the union’s first win in a Southern assembly plant owned by a foreign automaker.

Union President Shawn Fain said the pundits all told him that the UAW couldn’t win in the South.

“But you all said, ‘Watch this,’ ” he told a cheering group of VW organizers at a union hall in Chattanooga, Tennessee, when the UAW victory was clear. “You guys are leading the way. We’re going to carry this fight on to Mercedes and everywhere else.”

However, the UAW is likely to face a tougher test as it tries to represent workers at two Mercedes-Benz plants in Tuscaloosa, Alabama. A five-day election is scheduled to start May 13, where the union’s campaign has already become heated.

The UAW has accused the German carmaker of violating labor laws with aggressive anti-union tactics, which the company denies.

“They are going to have a much harder road in work sites where they are going to face aggressive management resistance and even community resistance than they faced in Chattanooga,” says a labor-relations professor at Cornell University, Harry Katz. “VW management did not aggressively seek to avoid unionization. Mercedes is going to be a good test. It’s the deeper South.”

Late last year, the UAW announced a drive to represent nearly 150,000 workers at non-union factories largely in the South. The union is targeting American plants run by Toyota, Honda, Hyundai, Nissan, Subaru, Mazda, Volkswagen, Mercedes, BMW and Volvo, along with factories operated by electric-vehicle makers Tesla, Rivian and Lucid.

The union’s last defeat at VW in Chattanooga came at a low-water mark — in the middle of a federal investigation into bribery and embezzlement under a previous president.

A business professor at Wayne State University in Detroit who studies the UAW, Marick Masters, said the union flipped the script by installing new leadership, touting the rich contracts it won last year from Detroit automakers after strikes at targeted factories, and exploiting a climate that is now more favorable to unions. He said the union was also adept at translating signed pro-union authorization cards into votes — partly by pushing for a quick election.

“Now the public and media eyes are going to be on Chattanooga and how quickly the UAW can translate this into a contract,” he said. If the union can’t quickly get a good contract, it risks losing some of the momentum it gained with Friday’s election win, he said.

Unions in other industries are already moving ahead with organizing campaigns in the South and trying to learn from the UAW’s playbook.

The Association of Flight Attendants, which has tried and failed to win over cabin crews at Atlanta-based Delta Air Lines, hopes to collect enough signatures to force another election at Delta by year end. The union’s president, Sara Nelson, said she was not surprised at the UAW win after strikes that led to record contracts last year.

“I’ve been talking about this for a long time — that strikes and taking on the boss is going to spur organizing, and that’s exactly what we saw here,” Ms. Nelson said.

Ms. Nelson is trying to secure an industry-leading contract at United Airlines that she can use to court Delta crews. In the meantime, crews at startup Breeze Airways, many of whom live in the South, will vote next month whether to join her union.

The White House issued a statement from President Biden congratulating the UAW. Mr. Biden — who joined a UAW picket line in Michigan during the union’s strike against Ford, GM and Stellantis plants last year — praised the success of unions representing autoworkers, Hollywood actors and writers, health care workers and others in gaining better contracts.

“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,” Mr. Biden said.

Mr. Biden criticized six Southern Republican governors, including Bill Lee of Tennessee, who told autoworkers this week that voting for union representation would jeopardize jobs.

Sharon Block, a law professor at Harvard University who worked for the Biden administration on labor and other issues, said the governors’ warning rang hollow after nonunion Tesla revealed that it plans to lay off 10% of its workers after disappointing sales results. She said VW workers saw the governors’ open letter as “an empty threat and a cynical ploy,” and they ignored it.

“Workers for a long time have been told that you can’t organize in the South. And many workers, even not in the South, may work in industries where they’ve been told for a long time you can’t organize,” Ms. Block said. “What the UAW showed last night is that we need to go and rethink all those negative statements.”

Associated Press