ObamaCare is poised to “destroy the foundation of the 40 hour work week that is the backbone of the American middle class.” And that’s the president’s supporters talking. The dire warning came last month in a letter from three of the nation’s most influential union bosses to Democratic leaders in Congress. “The unintended consequences of the ACA [Affordable Care Act] are severe,” the labor leaders bemoaned. “Perverse incentives are already creating nightmare scenarios.” Specifically, they noted, “the law creates an incentive for employers to keep employees’ work hours below 30 hours a week, and many of them are doing so...