When signing the bill raising California’s minimum wage, Governor Jerry Brown called the new $15 minimum wage “good politics” but “questionable policy.” He may be more prescient than many realize. There was a time in recent American history when a minimum wage of nearly equal magnitude to California’s was imposed, and “good politics” turned out to be disastrous policy. It is worth remembering this previous minimum-wage experiment as voters assess whether the progressive push for substantially higher minimum wages will deliver prosperity for the working class. President Obama has long supported the so-called Raise the Wage Act, which, if passed,...