The Republican Party's commitment to federalism has taken an interesting new turn: State governments under GOP control have been passing legislation to prohibit cities and counties from adopting minimum wages that would rise above the state level.

States have long been able to set their minimum wages above the federal rate, currently $7.25 an hour, and 29 currently do that, as does the District of Columbia. In recent years, when minimum wage activists have been unable to get statehouses to go along with increases, they have turned to local governments and had some notable successes. That has prompted some GOP-led states to nullify those efforts.

In mid-May, the Missouri legislature passed a bill that would override a St. Louis ordinance adopted last year that set the city's minimum wage at $10, well above the state rate of $7.70. Republican Gov. Eric Greitens was expected to sign it.

Republicans have said the pre-emption was necessary because the local rates were too disruptive for the state economy. "Fundamentally, we need to have a uniform, consistent minimum wage across the state so that we don't pit communities against each other," Sen. Dan Hegeman, R-Jefferson City, told reporters May 12 after the bill passed.

Aparna Mathur, economic policy scholar for the free-market American Enterprise Institute, said allowing multiple rates in a state can create serious problems for businesses. "There are large compliance costs with having to deal with a myriad of regulations across states and now across localities. For many businesses, the minimum wage hike in their state will already be a cost ... but now dealing with different minimum wages in different parts of the state (and across the country) imposes an additional cost," she wrote in an email.

Greitens would be the fourth Republican governor to sign such legislation in the last year. Iowa's Terry Branstad signed similar override legislation in March after officials in Polk County passed an ordinance to set their local minimum wage at $8.25, $1 above the state's level. In February, then-Alabama Gov. Robert Bentley signed legislation that nullified an effort by the Birmingham City Council to set its minimum wage at $10.10. Alabama also uses the federal minimum. Late last year, Ohio Gov. John Kasich signed legislation that stopped Cleveland from adopting a $15-an-hour rate, which is nearly double the state's rate of $8.25.

They weren't the first ones to do so. "I believe 25 states ... now have local minimum wage pre-emption laws on the books," sad Jackson Brainerd, policy associate for the nonpartisan National Conference of State Legislatures. Most have been on the books for years, he added. It's not clear what circumstances led to the passage of the older laws.

Dave Cooper, an economist with the liberal Economic Policy Institute, argued there is no reason why localities shouldn't have their own rates. He said compliance costs for business are overstated because the people mostly likely to receive the minimum wage are in the service and retail industries, which usually involve stationary locations.

"There is some hypocrisy here on the part of the Republicans," Cooper said. "They often say that policy should be left up to the states, but they don't seem willing to let the smaller subdivisions of government experiment."

Conservatives counter that there's nothing inconsistent with federalism to say that statehouses should be the ones to have the final word. "The pre-emption is not just about dealing with minimum wage hikes, but is also anticipating a slew of other regulations that are likely to come up at the state and local level. So I don't think it's hypocrisy — Republicans have traditionally favored lower regulations," Mathur said.