That membership dropped only slightly is somewhat surprising given how unfriendly the current administration is to organized labor.

In 2018, only 10.5 percent of workers in the United States were members of a union, a 0.2 percentage point decline from 2017, according to a report from the Bureau of Labor Statistics released last week. This represents a marked decline from 1983, the first year that the BLS began collecting this data, when 20.1 percent of U.S. workers were members of a union.

As with previous years, union membership rates were much higher for public-sector workers than private-sector workers. Nearly 34 percent of public-sector workers belonged to a union, in comparison to only 6.4 percent of private-sector workers (both public- and private-sector rates declined slightly in 2018). Men and African Americans were more likely to be in unions, and two industries—protective service occupations (firefighters, detectives, animal control, etc.) and education, training, and library occupations—exhibited the highest rates of unionization in 2018.

Union membership has been steadily declining in the U.S. for decades, driven largely by declines in private-sector union membership. Historians and economists attribute the collapse of the American union to a range of factors—the damage that economic forces did to traditionally unionized manufacturing industries beginning in the 1970s; the 1947 Taft-Hartley Act, which allowed states to pass right-to-work laws, and the subsequent failure to unionize the south (where union membership rates are still dramatically lower than the rest of the country); growing anti-union and anti-government sentiment (particularly in the GOP); and the lack of a true "labor" party in America.

That union membership slipped only slightly in 2018 is somewhat surprising given how unfriendly the current administration is to organized labor. The Trump administration has issued executive orders targeting public-sector unions, meant to make it easier to fire federal employees, but they were struck down by a federal judge. It has also appointed two business-friendly Supreme Court justices. In the court's most notable ruling, newly appointed Justice Neil Gorsuch joined Justices Samuel Alito, Clarence Thomas, Anthony Kennedy, and John Roberts to strike down so-called "agency fees," mandated payments by non-union members to unions in their bargaining unit, a decision that some advocates warned would decimate public-sector unions.

At the same time, workers, including "alt-labor" organizations—groups that fight for workers' protections but don't collectively bargain—have wracked up some notable gains in recent years, from teachers strikes in red states, to the Fight for $15 federal-minimum-wage movement, to successful campaigns for paid sick leave around the country. As one labor historian, Joseph McCartin, a professor at Georgetown University and the executive director of the Kalmanovitz Initiative for Labor and the Working Poor, told Pacific Standard last year, the loss of agency fees might have an unintended effect, leading unions to start once again become social movements, "taking on fights that help them build and keep a loyal membership in an environment where no one is required to support the union that bargains for them."

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