The notion of a “job guarantee” in America, once appropriately seen as a fringe idea lacking credibility, is growing in popularity among the Democratic Party. Last week, the Washington Post reported that Democratic socialist Sen. Bernie Sanders of Vermont is crafting a proposal in which the federal government would guarantee a job that pays $15 an hour plus health insurance to any American “who wants or needs one.” The plan, which Sanders hasn’t figured out how to fund yet, would call for the creation of hundreds of government projects throughout the country in fields ranging from infrastructure to caregiving in...