Mercedes Workers in Alabama Reject Union

The election, fiercely opposed by the state’s political leaders, was seen as a test of the United Automobile Workers’ ability to unionize factories in the South.

Workers at two Mercedes-Benz factories near Tuscaloosa, Ala., voted on Friday against joining the United Automobile Workers, a stunning blow to the union’s campaign to gain ground in the South, where it has traditionally been weak.

The defeat came after Kay Ivey, Alabama’s governor, and other Republican leaders argued that a pro-union vote would choke off the investment that has transformed the state into a major auto producer. Hyundai and Honda also have large factories in Alabama that the U.A.W. is trying to organize.

The vote took on national significance as a test of whether the U.A.W. could build on a string of recent victories and gain ground in a state whose elected officials have been hostile to organized labor. The union has said it wants to organize every automobile factory in the United States, expanding its membership to include the employees of companies like Toyota and Tesla.

But the loss at the Mercedes plants will almost surely slow down the union’s campaign and probably force it to do more spadework to secure the support of workers before seeking to hold elections at other auto plants. Union leaders will want to spend time figuring out how best to counter the messages and tactics of local lawmakers and company executives.

“It hurts to lose, no doubt,” Elizabeth Shuler, president of the A.F.L.-C.I.O., said on Friday. “But we see it not as a loss, but a temporary setback. Workers will persevere no matter what it takes.”

Mercedes workers voted 56 percent to 44 percent against joining the union, according to the National Labor Relations Board, which oversaw the election. Close to 4,700 ballots were cast, representing a large majority of the 5,075 employees who were eligible to vote.