Pennsylvania’s judicial-retention election was the biggest in the commonwealth’s history. This seemingly innocuous off-year election drew at least $20 million–much of which came from outside the state–and garnered significant national attention, including statements by President Donald Trump and former President Barack Obama.

But of all the biggest influences in this election, few were as prominent as labor unions.

Among the top spenders was Pennsylvanians for Judicial Fairness (PJF). This Super PAC reported the largest number of independent expenditures, raising about $5 million and spending $3.4 million on pro-retention electioneering as of the last report. PJF composed nearly one-third of total spending on election advertisements, according to the Brennan Center.

PJF has served as a well-funded political machine for unions. Its largest donors include two of the most prominent national government unions: the Service Employees International Union (SEIU) and the American Federation of State, County and Municipal Employees (AFSCME). The Fund for Student Success, another significant PJF contributor, is a super PAC established by the Pennsylvania State Education Association (PSEA).

Ultimately, this large-scale investment tipped the scales. One analysis showed the victorious pro-retention side spent four times more money on advertising than the opposition. This disparity will likely grow once all parties have filed their final campaign finance reports.

Yet, this pattern isn’t unique to Pennsylvania. In fact, it’s part of a national story about how Big Labor has become a powerful force in American politics.

And to finance their political activities, unions increasingly rely on membership dues. Traditionally, membership dues have funded activities like legal representation and collective bargaining for members.

However, unions have politicized their finances. A report by the Commonwealth Foundation shows that most union political spending originates from membership dues. The same report also found that the four largest public sector unions–SEIU, AFSCME, the American Federation for Teachers, and the National Education Association–spent more of members’ dues on political activism and electioneering than on member representation.

This politicking addresses a litany of progressive and left-leaning causes. Often, these issues are unrelated to the workplace–everything from pro-abortion advocacy to quixotic Democratic campaigns. (About 99 percent of union-funded candidates are Democrats.)

Unions’ partisanship doesn’t necessarily align with that of their rank-and-file members.

The New Jersey Education Association (NJEA) spent $40 million in membership dues to support its president, Sean Spiller, in his failed gubernatorial campaign. However, several NJEA members didn’t agree to fund any political campaigns.

“When I signed my union membership card, I did not check the back saying I wanted to contribute to the union political action committee,” writes Marie Dupont, a teacher and NJEA member, in The Wall Street Journal. “That was a contract stating my dues wouldn’t go to the union political apparatus, but a handful of insiders ignored that choice and broke that trust.”

NJEA funneled general funds through Garden State Forward, Working New Jersey, and Protecting Our Democracy–all election-focused organizations that not only backed Spiller but also were headed by the NJEA president. These questionable activities landed NJEA in court with a lawsuit alleging that the union misled its members, including Dupont, who is a lead plaintiff.

NJEA isn’t alone; other unions have found themselves in legal hot water for their activism. For example, in 2022, six college professors sued their union for its anti-Israel activism.

Union electioneering has morphed into a complex shell game. As demonstrated by NJEA, unions funnel funds–again, financed predominantly by dues–through a sprawling web of “dark money” groups, including super PACs, 527s, and politically active nonprofits.

Despite this opaque quasi-laundering scheme, one thing is clear: Over the past 15 years, government unions have used membership dues to advance overtly political agendas–often behind the backs of their own members.

Unions once played a role in securing workplace rights and fair pay. But as they evolve into partisan megadonors, they drift away from the workers whose dues fuel this political machine.

David R. Osborne is the Senior Director of Labor Policy with the Commonwealth Foundation, Pennsylvania’s free-market think tank.