Since Donald Trump took office, many liberals have looked to cities and states as central fronts in the Democratic resistance. With a president hostile to progressive policies of all kinds, the thinking goes, state legislatures and city councils offer more hope for action on a wide range of issues, from regulating carbon emissions to defending immigrant rights.

Nowhere has the “think local” strategy seemed more promising than in the fight to increase the minimum wage. Since 2004, 34 localities from Maryland to New Mexico have raised the minimum wage above their state levels. In November, four states—Arizona, Maine, Colorado, and Washington—passed ballot measures to raise the minimum wage above its current federal level of $7.25 an hour. In a deeply divided country, it’s a policy that commands strong bipartisan support: 74 percent of Americans say they want to raise the minimum wage, and the Maine measure passed with 420,000 votes—more than any ballot initiative in state history.

But Republicans and their business allies are fighting back with a two-pronged strategy. First, they’re working to derail the minimum-wage increases that have already passed. Business groups in Washington and Arizona have gone to court to block the November ballot initiatives, and lawmakers in Maine have introduced a number of bills that seek to roll back or weaken the wage increase. Second, in violation of their much-lauded belief in decentralized government, Republicans are moving aggressively to block more cities and states from boosting the minimum wage. In Arizona, GOP lawmakers have approved bills that make it harder to pass citizen ballot initiatives, a democratic process enshrined in the state constitution for more than a century. And legislatures in 24 states have passed so-called “preemption bills” to block cities and counties from passing their own minimum-wage hikes. Many of the bills are the product of model legislation written by the Koch-backed American Legislative Exchange Council, which has made the fight against minimum-wage increases a top priority.

In March, Iowa became the latest state to pass a preemption bill to block minimum-wage increases. The legislation not only bars any more local wage hikes, it also voids measures that already passed in four counties. The move was made possible by GOP victories in November, which gave Republicans in Iowa control of both the state legislature and the governor’s mansion for the first time in almost two decades. “We’d heard rumblings last year, but nothing was even drafted,” says Bridget Fagan-Reidburn of the Iowa Citizens for Community Improvement Action Fund, a grassroots organizing group. “But once Republicans won the state senate, this was one of their priorities.”

The Iowa bill is particularly egregious because it actually lowered the minimum wage for 65,000 workers in the state who were already enjoying hourly increases of up to $3 in their counties. Those extra dollars make a huge difference to working-class Americans. Mazahir Salih, a community organizer with the Center for Worker Justice in Iowa, recalls meeting one woman who was able to stop working on weekends after her county raised the minimum wage, enabling her to spend more time with her children. Now, thanks to the GOP’s preemption bill, things look a lot worse for workers in the state. “A lot of people are really worried,” says Salih. “They tell me stories of how they were suffering at $7.25 and how they could not even make ends meet.”