CHATTANOOGA, Tenn. — Employees at a Volkswagen factory in Chattanooga, Tennessee, overwhelmingly voted to join the United Auto Workers union Friday in a historic first test of the UAW’s renewed effort to organize nonunion factories.

The union wound up getting 2,628 votes, or 73% of the ballots cast, compared with only 985 who voted no in an election run by the National Labor Relations Board.

Both sides have five business days to file objections to the election, the NLRB said. If there are none, the election will be certified and VW and the union must “begin bargaining in good faith.”

President Joe Biden, who backed the UAW and won its endorsement, said the union’s win follows major union gains across the country including actors, port workers, Teamsters members, writers and health care workers.

“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,” he said in a statement late Friday.

Twice in recent years, workers at the Chattanooga plant have rejected union membership in plantwide votes. Most recently, they handed the UAW a narrow defeat in 2019 as federal prosecutors were breaking up a bribery-and-embezzlement scandal at the union.

But this time, they voted convincingly for the UAW, which is operating under new leadership directly elected by members for the first time and basking in a successful confrontation with Detroit’s major automakers.

The union’s pugnacious new president, Shawn Fain, was elected on a platform of cleaning up after the scandal and turning more confrontational with automakers. An emboldened Fain, backed by Biden, led the union in a series of strikes last fall against Detroit’s automakers that resulted in lucrative new contracts.

The new contracts raised union wages by a substantial one-third, arming Fain and his organizers with enticing new offers to present to workers at Volkswagen and other companies.

Next up for a union vote are workers at Mercedes factories near Tuscaloosa, Alabama, who will vote on UAW representation in May.

Worker Vicky Holloway of Chattanooga was among dozens of cheering workers celebrating at an electrical workers union hall near the VW plant. She said the overwhelming vote for the union came this time because her colleagues realized they could have better benefits and a voice in the workplace.

“Right now we have no say,” said Holloway, who has worked at the plant for 13 years and was there for the union’s previous losses. “It’s like our opinions don’t matter.”

Michael Ream, who has worked assembling vehicles at the Chattanooga plant since 2019, said he voted for the union because he was inspired by the contracts it won with Detroit automakers after going on strike last year.

In a statement, Volkswagen thanked workers for voting and said 83.5% of the 4,300 production workers cast ballots in the election.

Six Southern governors, including Tennessee’s Bill Lee, warned the workers in a joint statement this week that joining the UAW could cost them their jobs and threaten the region’s economic progress.

But the overwhelming win is a warning to nonunion manufacturers, said Marick Masters, a business professor at Wayne State University in Detroit who studies the union.

“This is going to send a powerful message to all of those companies that the UAW is knocking at the door, and if they want to remain nonunion, they’ve got to step up their game,” Masters said.

He expects other nonunion automakers to become more aggressive at the plants, and that anti-union politicians will step up their efforts to fight the union.

Shortly after the Detroit contracts were ratified, Volkswagen and other nonunion companies handed their workers big pay raises.

Last fall, Volkswagen raised production worker pay by 11%, lifting top base wages to $32.40 per hour, or just over $67,000 per year. VW said its pay exceeds the median household income for the Chattanooga area, which was $54,480 last May, according to the U.S. Labor Department.

But under the UAW contracts, top production workers at GM, for instance, now earn $36 an hour, or about $75,000 a year excluding benefits and profit sharing. By the end of the contract in 2028, top-scale GM workers would make over $89,000.

The VW plant will be the first the UAW has represented at a foreign-owned automaking plant in the South. It will not, however, be the first union auto assembly plant in the South. The UAW represents workers at two Ford assembly plants in Kentucky and two GM factories in Tennessee and Texas, as well as some heavy-truck manufacturing plants.

Also, more than three decades ago, the UAW was at a Volkswagen factory in New Stanton, Pennsylvania, east of Pittsburgh. VW closed the plant that made small cars in the late 1980s.

Krisher reported from Detroit. Associated Press journalist Chris Megerian contributed from Washington.