This year the Republican war on unions has returned with a vengeance. In former labor stronghold Illinois, GOP Gov. Bruce Rauner is pursuing right-to-work legislation — which allows workers to gain the benefits of union representation without paying dues — and looks likely to succeed. Wisconsin became a right-to-work state last month, and its Republican Gov. Scott Walker looks set to ground a presidential bid in union busting, recently saying his political fight with unions prepared him to take on the Islamic State in Iraq and the Levant. The Supreme Court appears ready to overrule its Abood v. Detroit Board of Education decision, which allows unions to collect dues from nonmember public sector workers who nonetheless benefit from collective bargaining.

With the enemies at the gate, the liberal elite seems to have finally learned to love unions. Nicholas Kristof writes that, contrary to his earlier opinion, “we should strengthen unions, not try to eviscerate them.” Former Treasury Secretary Robert Rubin, a key architect of Bill Clinton’s finance-friendly economic policy, recently argued, “Measures that facilitate collective bargaining can result in a broader participation in the benefits of productivity and growth.” And in “The Report of the Commission on Inclusive Prosperity,” which is likely to become the centerpiece of Hillary Clinton’s presidential campaign, the commission, co-chaired by Ed Balls and Lawrence Summers, concludes that “we need to support the growth of unions.”

But it may be too little, too late. Democrats did little to defend unions when it counted. Under President Jimmy Carter, Alfred Kahn began deregulating the airlines. Carter then signed into law legislation deregulating railroads and trucking (both hobbling powerful unions). President Bill Clinton pushed for the North American Free Trade Agreement against union opposition and deregulated finance, greatly empowering capital. To be fair, some of these pressures came from global trends, but public policy played a key role in tilting the field against labor. Now Republicans are fighting to drive a final spike in the heart of the most effective anti-inequality movement in history. If liberals do nothing to shore up unions, their decline will only continue. That will have important implications for inequality.

What unions do

Unions not only give their members a voice at work but also can have much broader political effects. By mobilizing voters and contributing to campaigns, organized labor is in effect the only lobbying group operating in the interest of ordinary Americans.

In a 1998 study, political scientists Benjamin Radcliff and Martin Saiz found that “the relative strength of the labor movement across the American states is one of the principal determinants of policy liberalism.” They found that the rate of unionization has a dramatic effects on spending for Aid to Families With Dependent Children and education as well as on tax progressivity and that these effects are stronger than Democratic governors and Democratic legislatures. As Radcliff told me, “strong labor unions are able to influence public policy, so as to create programs … that benefit everyone in society, not merely organized workers.”