The evidence is already coming in: Mandatory increases in Los Angeles, San Francisco and Seattle have cost thousands of jobs

See A Post-Labor Day, Minimum-Wage Hangover by Andy Puzder. Mr. Puzder is the chief executive officer of CKE Restaurants.

"It’s still early to know how the hikes are affecting the job market, but the preliminary data aren’t good. Mark Perry of the American Enterprise Institute, Adam Ozimek of Moody’s Analytics and Stephen Bronars of Edgewood Economics reported last month that the restaurant and hotel industries have lost jobs in all three cities. Mr. Bronars crunched the numbers and discovered that the “first wave of minimum wage increases appears to have led to the loss of over 1,100 food service jobs in the Seattle metro division and over 2,500 restaurant jobs in the San Francisco metro division.” That is a conservative estimate, he notes, as the data include areas outside city limits, where the minimum wage didn’t increase."

"This comes as no surprise. In 2014 the Congressional Budget Office found that increasing the minimum wage to $10.10 an hour would result in employment falling by 500,000 jobs nationally. By the way, less than 20% of the earning benefits would flow to people living below the poverty line, as University of California-Irvine economist David Neumark has pointed out.

That such laws help people who have jobs and manage to keep them but hurt those without a job helps explain San Francisco’s wealth disparity. Before the spate of recent increases, San Francisco’s minimum wage—$10.74 an hour—was the highest in the country. It has been among the top for a long time. If minimum wages helped alleviate income inequality, you’d expect San Francisco to show it.

Not so. San Francisco ranks second in income inequality among the top 50 cities in the U.S., behind only by Atlanta, according to a 2014 Brookings Institution report. The number of households in the area earning less than $25,000 a year is growing while the middle class shrinks, according to a 2014 report from the city’s Human Services Agency. San Francisco’s income distribution is roughly on par with Rwanda’s, though it edges out Guatemala’s.

It’s understandable that people who have jobs would like a raise. But what about the people who don’t have jobs? The national labor-participation rate is 62.6%—the lowest since the Carter administration—and a wage increase means little to the 5.9 million Americans who aren’t in the labor force but want a job now. The same goes for the 6.5 million Americans working part time because they’re unable to find full-time opportunities."