Looming over the United Auto Workers strike: Automakers’ continued migration to the anti-union South.

Beginning in the 1970s and 1980s, the auto industry began shifting South, a region long characterized by hostility to labor unions and by low wages.

Since then, assembly lines of higher-paid UAW workers at Detroit’s Big Three – Ford, General Motors and Stellantis – have shrunk. And automakers such as Volvo, Mercedes-Benz, BMW, Toyota and Hyundai have steadily hired nonunion autoworkers, who make less money for substantially the same work, in the South.