House Republicans are investigating several US labor unions based on claims from far-right nonprofits alleging union dues are being used for illegal political funding.

Republicans on the House’s education and workforce committee opened the investigation this summer after multiple reports from the conservative thinktanks targeted unions and their spending, claiming that unions are using member dues to support Democratic causes.

While unions are allowed to advocate for political causes, they are prohibited from using union dues to directly fund specific candidates or political action committees (Pacs). Union members can voluntary donate to labor union’s political action committees.

The unions under investigation include the American Federation of Teachers (AFT), United Auto Workers, United Steelworkers, Smart Transportation Division (Smart-TD), Brotherhood of Locomotive Engineers and Trainmen (BLET), and the Brotherhood of Maintenance of Way Employees Division (BMWED).

The allegations come from research reports by the American Accountability Foundation (AAF), a “dark money” nonprofit that counts Project 2025 architect the Heritage Foundation as a donor, and the Freedom Foundation, a conservative thinktank whose chairman once protested against Labor Day, claiming “I can’t think of a problem in society that can’t be traced in some way back to the abuses of organized labor.”

Among the AAF’s allegations toward labor unions include complaining that the BLET supported a lawsuit filed by the UAW to halt the Trump administration’s attempt to end collective bargaining. It also highlighted the BLET’s criticism of Project 2025, which advocates for several policies that would weaken labor unions and collective bargaining rights.

“The industrial unions the [House] committee is investigating have become glorified political arms of the Democrat Party,” said Tom Jones, President of the American Accountability Foundation in a statement. “When these unions care more about their friends in Congress than their members in the factories and railroads, it becomes clear they’re not serving the working men and women of America!”

In a statement, a spokesperson for United Steelworkers said the group is “working diligently on fully addressing the committee’s request”.

“Our union values transparency and annually reports our spending with the Department of Labor,” the spokesperson said.

As a part of their union probes, House Republicans are also investigating AFT president Randi Weingarten after the Freedom Foundation claimed, using speculation around the union’s annual financial filing, that union member dues funded her 2025 book, Why Fascists Fear Teachers: Public Education and the Future of Democracy.

“Perhaps Weingarten’s next book should be entitled, Why Teachers Fear Teachers Unions,” the analysis claimed.

In a letter responding to the allegations, Michael Bromwich, an attorney representing Weingarten and AFT, called the Freedom Foundation’s report “a partisan attack masquerading as investigative journalism”.

“Its claims are premised on factual inaccuracies, misleading characterizations, and a willful disregard for the complete record,” Bromwich wrote. “The documents produced to the House committee refute these allegations and demonstrate that the book project was lawfully and ethically undertaken to advance AFT’s mission, with appropriate oversight and transparent financial arrangements.”

The Freedom Foundation and House Republicans on the investigating committee did not respond to multiple requests for comment.

The House investigations follow reports that the Trump administration conducted surveillance of labor unions in Minnesota during a mass anti-immigration enforcement operation earlier this year, including the CWA and the SEIU.

Cathy Creighton, director of Cornell University’s sSchool of Industrial and Labor Relations Buffalo Co-Lab, said that union finances are strictly controlled, with disclosure requirements on how money is spent – which is how the conservative groups got the information for their reports.

Most union members vote Democrat, because the party “has a platform that supports the labor movement, the right to organize [and] the right to bargain”, Creighton said.

“The labor movement is allowed to spend money on political actions, and they do,” she said, noting that the motivation behind the reports seem political. “The Trump administration has been trying to eliminate bargaining rights and unions, full stop.”

A 2024 poll by Gallup found 62% of Americans say the Democratic party best serves the interest of union members compared to 27% who said the same about the Republican party.

US labor unions have historically supported Democrats over Republicans since Franklin Delano Roosevelt’s administration passed the National Labor Relations Act in 1935. But Republican presidents, up until Ronald Reagan in the 1980s, refrained from taking hostile positions toward labor unions and collective bargaining.

In 1976, Republican Gerald Ford’s presidential campaign stated “free collective bargaining remains the best way to insure that American workers receive a fair price for their labors.”

But under Reagan, the Republican party began to emphasize so-called “right to work” laws over collective bargaining and adopted more hostile, pro-business stances toward labor unions.

Under Trump’s second term, he issued an executive order to rescind collective bargaining rights from more than 1 million federal workers and made cuts to federal agencies tasked with enforcing labor laws.