In “The Wealth of Nations,” the founding text of free-market economics, Adam Smith took it for granted that workers should be paid enough to cover the living costs of themselves and their dependents. “A man must always live by his work, and his wages must at least be sufficient to maintain him,” wrote Smith. “They must even upon most occasions be somewhat more, otherwise it would be impossible for him to bring up a family, and the race of such workmen could not last beyond the first generation.”

In the last half-century, policy makers of both parties in the U.S. have successfully refuted Adam Smith. It turns out that it is indeed possible to pay wages to workers that are too low for their own maintenance, much less that of their families. This depends on using means-tested welfare programs like the earned-income tax credit (EITC), food stamps and housing vouchers, all of which compensate for wages that are too low for workers to live on.