No wonder Republicans hate unions so much—they fight income inequality

If you don’t like soaring economic inequality, you should like unions. A recent study by three Princeton University economists found that unions reduced income inequality in the United States, not just for union members but beyond:

Union workers now earn about 20 percent more than nonunion workers in similar jobs. Remarkably, this union premium has held steady since the 1930s. [...]

… the researchers broadened their lens to include the entire distribution of workers and their wages beyond those who are in typically unionized jobs and industries. They found that, going back to the 1930s, more unions meant more income equality. During years and in states where workers were more likely to be unionized, income inequality was lower.

An earlier study by sociologists Bruce Western and Jake Rosenfeld had a similar finding, that “unions not only equalize union members' wages, they also equalize the nonunion wage distribution by threatening union organization and buttressing norms for fair pay. We found strong evidence that unionization rates in detailed industries for geographic regions are positively associated with wage equality among nonunion workers.”

The Supreme Court’s recent Janus decision took aim at worker and union strength—and as a result, may further contribute to U.S. income inequality more broadly.