“Preemption is portrayed as a struggle between political parties, but state interference in city minimum wage laws stems from a larger Jim Crow legacy of blocking economic policies that primarily benefit communities of color,” said Nikki Fortunato Bas, the executive director of PWF. “Both Democratic and Republican governors have approved preemption laws, but in most cases, it’s predominantly white legislatures overturning municipal laws passed by majority black cities. Ending this ugly pattern of white interference is critical to realizing racial and economic equity.”

While Missouri’s law is only one of many preemption laws on wages, it is unusual if not unprecedented in actually reversing an increase that has already gone into effect. (Kansas City voters also voted to increase the minimum wage in August, and that hike briefly went into effect, meaning that Kansas City workers also briefly saw a raise.)

Douglas, who is African American, said the extra money she earned for those three months made a real difference in her life. She works full-time and cares for two sons, and she says she doesn’t want a hand-out but thinks she should be able to provide for her family with a full-time job. With the higher wages, she was able to start paying down old bills, but now she’s not sure how she’ll keep her electricity on.

“Yesterday I wasn’t really able to eat, because I wanted to make sure [my 16-year-old son] eats. I’m robbing Peter to pay Paul,” Douglas, 59, said. “I’m not asking for a million dollars. I’m not talking about going on cruises.” (P&P Restaurants, which owns the franchise where Douglas works, did not immediately respond to a request for comment.)

According to MIT’s living-wage calculator, the living wage for a single adult in St. Louis County is $10.43 per hour. For an adult and two children, it’s $26.44. The poverty wage for an adult and two children is $9 per hour—less than what Douglas made for the last three months, but more than her new, reduced salary.

The rise of minimum-wage preemption laws has been driven by business interests, and in particular by the American Legislative Exchange Council, or ALEC, which has circulated model legislation taken up by many states. ALEC and other business groups argue that a “patchwork” of wage laws in different places makes it difficult for companies to do business. But lots of laws work by patchwork, and different workers make different amounts even in the same place. ALEC did not immediately respond to a request for comment.

In approving the law, Missouri Governor Eric Greitens, a Republican, cited a study of the effects of Seattle increasing its minimum wage to $13 per hour, part of a planned increase to $15 per hour. The study found that while some workers benefited from the increase, others saw their hours cut, resulting in a net decrease in their take-home pay. As my colleague Annie Lowrey wrote when the study came out, it is a single study, and it’s at odds with years of other work on minimum-wage increases. Seattle also set its wage higher than other cities. But it is a real-world example that calls into question what the tradeoffs of higher wages might be.