Tens of thousands of people who work for Toyota in Kentucky, Mercedes-Benz in Alabama or Tesla in Texas are technically not involved in the high-stakes negotiations taking place between labor and management in and around Detroit.
But they are very much a presence.
Executives at Ford Motor, General Motors and Stellantis, the parent of Chrysler, invoke nonunion automakers, many of them in the South, as a competitive threat that makes it impossible for them to meet striking workers’ demands for big raises, more generous benefits and better working conditions.
“Toyota, Honda, Tesla and others are loving this strike because they know the longer it goes on, the better it is for them,” Bill Ford, the executive chair of Ford Motor, said in Michigan last week. “They will win, and all of us will lose.”
The United Automobile Workers union sees such statements as an attempt to play workers off one another. It views the strikes, entering their sixth week, as a first step toward better pay for not only U.A.W. members but also the nonunion workers that it plans to recruit in the future.
“We won’t be used in this phony competition,” Shawn Fain, the U.A.W. president, said on Friday, reacting to Mr. Ford’s speech. He added, “Nonunion autoworkers are not the enemy. Those are our future union family.”
The pay gap between union and nonunion factories has long been a point of contention. Some industry executives have argued that high union wages were a big reason G.M. and Chrysler had to resort to bankruptcy after the 2008 financial crisis.
Union leaders and progressive lawmakers have asserted that the growth of nonunion manufacturing, mostly in the South but also in the Midwest and West, has helped to erode the middle class over the past several decades.
Veteran union autoworkers tend to make more than production workers who are not represented by unions. They often have more say in their schedules and overtime work.
But starting pay at Ford, G.M. and Stellantis factories can be lower than at nonunion factories. And the pay of nonunion workers at Southern auto plants tends to go further because the cost of living there is lower than it is in the Midwest.
Even the geographic divide between union and nonunion plant is not always as clear as it may seem. Toyota and Honda have plants in the South, where unions are weak, but they also have factories in Ohio and Indiana, where unions are stronger. And G.M. and Ford have union operations in Kentucky, Tennessee and Texas.
The debate about auto industry wages has become more urgent as automakers invest billions to build factories that produce batteries for electric cars. Most of those factories are being built in Southern states, like Georgia and Tennessee, where local laws make it more difficult for unions to organize a factory.
“A good agreement with the Detroit Three would be powerful because it gives union organizers better arguments for joining the union,” said Ian Greer, a Cornell research professor who studies the effect of electric vehicles on labor.
Even with a union wage of almost $32 an hour from her job assembling chassis at a Ford factory in Chicago, Schataan Lyke said she did not have it easy. She is the sole breadwinner for three children and worries about how to afford a prom dress for her oldest.
Ms. Lyke, who has been on strike, said she was glad to have the union behind her. “You’ve got someone on the outside fighting for you,” she said.
But Ms. Lyke, 37, has it better than people doing similar work in the South. At a Nissan factory in Canton, Miss., Morris Mock, 49, makes about $1 less than Ms. Lyke per hour even with more than 20 years of experience, he said.
An attempt to unionize Nissan in 2017 failed to win enough support from workers. That means Mr. Mock, one of the people who led the union drive, will not benefit directly from the contract that the U.A.W. works out with automakers. But he said he was glad the union was fighting to protect wages as the industry switched to electric vehicles.
“The market is about to change,” Mr. Mock said. “I’m glad that they understand that we must put workers first.”
Government statistics suggest wide regional pay gaps. Michigan autoworkers make 22 percent more than production workers in Tennessee, 23 percent more than South Carolina workers and 28 percent more than Alabama workers, according to a Census Bureau survey. Those figures include people who work for suppliers, where pay is often lower than in factories that assemble vehicles.
Some labor experts said the bigger difference between union and nonunion autoworkers had less to do with pay and more with things like mandatory overtime and the scheduling of shifts. Union workers tend to have more say in those matters.
The auto industry has been moving South for decades, drawn by lower costs, weak unions and local government incentives. Foreign automakers have often chosen sites in the South when they set up factories in the United States. BMW and Volvo Cars have factories in South Carolina; Mercedes and Hyundai in Alabama; Toyota in Kentucky; and Volkswagen in Tennessee.
Most of the foreign automakers do not disclose what they pay their workers. Volkswagen, an exception, said the starting pay at its factory in Chattanooga, Tenn., was $21.10 for hourly production workers. Veteran workers earn more than $29, the company said.
Foreign automakers concentrated in the South sometimes pay their U.S. workers more than Ford, G.M. and Stellantis, according to a study by EY for Autos Drive America, an industry association that represents Nissan, Toyota, Mercedes and others.
The average starting wage at foreign automakers was $19 an hour, the survey said, more than the $17 starting wage for U.A.W. members. But the average maximum pay at the foreign automakers was $28, compared with $32 for U.A.W. members under the current contract.
A Nissan spokesman declined to say how much the company pays its U.S. workers, but he said the average was higher than that reported by the Autos Drive America survey.
Tesla, which is based in Texas and has factories there and in Buffalo; Fremont, Calif.; and Sparks, Nev., does not disclose what it pays its workers, but the Detroit automakers say it is less than what they pay.
Ford has said its labor costs, including benefits and bonuses, are 40 percent more per worker than Tesla’s. That figure does not include stock awards that at least some Tesla employees receive. On Tesla’s website, job advertisements for a production associate pay $20 to $23 an hour.
Even if autoworker pay in Alabama or Mississippi is less than what it is in Michigan or Illinois, it is often more than what employers in other industries pay in those places.
Working conditions are often a bigger issue than pay, labor representatives say.
In February, Emily Erickson of the University of Warwick in England and Berneece Herbert of Jackson State University published a survey of 211 workers at Mercedes’s factory in Vance, Ala., near Tuscaloosa.
The workers reported earning an average of $27 an hour at Mercedes, high for the region. But they said they were forced to work overtime or change their work schedules with little notice. Almost half worked more than 50 hours a week. The study also found that white workers made an average of $3 more per hour than Black workers.
Mercedes denied that it discriminates. “Our pay structure is equal for all team members regardless of race, age or ethnic origin, and our pay progressions are based on seniority,” the company said in a statement.
It noted that the company employed 6,000 people in Alabama, suggesting that the study sampled too few workers. “We do not agree with its conclusions,” Mercedes said.
The gulf between pay in the South and the North is certain to widen when Ford, G.M. and Stellantis agree on new contracts with the U.A.W. The union is demanding a 40 percent increase over four years. Ford, G.M. and Stellantis have already offered raises of 23 percent and could go higher.
Unions have made some progress in the South recently. Workers at Blue Bird, which makes school buses in Georgia, voted to join the United Steelworkers in May and are negotiating a contract. Workers at ZF, which makes axles for Mercedes in Alabama, ended a monthlong strike last week after the German company agreed to raise the top hourly wage to $23.
Labor leaders say they have already been deluged with calls from workers at Toyota, Volkswagen and Hyundai who expressed interest in organizing unions. Workers at Volkswagen voted not to join the union in 2019, but the environment may be different this time.
“These workers will say, ‘Look what the U.A.W. did for these workers at G.M., Ford and Stellantis,’” said Tim Smith, director of U.A.W. Region 8, which includes all of the Southeast.
“We’ve got organizers on the ground there right now,” he said. “We’re starting to make our move.”
Ben Casselman and Bob Chiarito contributed reporting.