Kevin Williamson of National Review Online pokes holes in the “magical thinking” surrounding the political push for a higher government-mandated minimum wage.

Thanks to a new study from economists at the University of Washington, American progressives have learned that the laws of supply and demand apply to the labor market. Everybody already knew that, except for professional economists.

The study, commissioned by the city government of Seattle and published by the National Bureau of Economic Research, found that Seattle’s law incrementally raising its minimum wage — to $13 an hour last year, en route to $15 — resulted in low-wage workers’ earning less money rather than more. This surprised many in Seattle, who had been assured by all the best economists, including Paul Krugman, that such a thing would not come to pass.

So, what happened?

The short version is: You can pass a law saying you have to pay low-wage workers more, but you cannot pass a law that says you have to hire them in the first place, or that you cannot cut back on hours when the price of hourly labor goes up. As businesses responded to the new higher labor costs by reorganizing their processes in less labor-intensive ways (the classic examples here are the replacement of wait staff with computer screens in restaurants and the replacement of bank clerks with more sophisticated ATMs), the law that was supposed to increase low-wage workers’ incomes actually reduced them — substantially, by an average of $125 a month.