As workers’ power has waned, many corporations have adopted practices that were far rarer — if not unheard-of — decades ago: hiring hordes of unpaid interns, expecting workers to toil 60 or 70 hours a week, prohibiting employees from suing and instead forcing them into arbitration (which usually favors employers), and hamstringing employees’ mobility by making them sign noncompete clauses.

America’s workers have for decades been losing out: year after year of wage stagnation, increased insecurity on the job, waves of downsizing and offshoring, and labor’s share of national income declining to its lowest level in seven decades.

Numerous studies have found that an important cause of America’s soaring income inequality is the decline of labor unions — and the concomitant decline in workers’ ability to extract more of the profit and prosperity from the corporations they work for. The only time during the past century when income inequality narrowed substantially was the 1940s through 1970s, when unions were at their peak of power and prominence.