Amazon.com has joined rocket maker SpaceX and grocery chain Trader Joe’s in claiming that a U.S. labor agency’s in-house enforcement proceedings violate the U.S. Constitution, as the retail giant faces scores of cases claiming it interfered with workers’ rights to organize.

Amazon in a filing made with the National Labor Relations Board (NLRB) on Thursday said it plans to argue that the agency’s unique structure violates the company’s right to a jury trial.

The company also said that limits on the removal of administrative judges and the board’s five members, who are appointed by the president, are unconstitutional.

The filing came in a pending case accusing Amazon of illegally retaliating against workers at a warehouse in the New York City borough of Staten Island, where employees voted to unionize in 2022. Amazon, which has faced more than 250 NLRB complaints alleging unlawful labor practices across the country in recent years, has denied wrongdoing.

SpaceX is making similar claims against the board in a lawsuit filed last month, one day after the labor board accused the company of firing eight engineers for criticizing CEO Elon Musk in a letter to company executives.

Trader Joe’s raised the arguments later in January at a hearing in an NLRB case, and two Starbucks baristas seeking to dissolve their unions have challenged the board’s structure in separate lawsuits.

An NLRB spokeswoman declined to comment.

The board’s general counsel issues complaints against employers alleging violations of federal labor law. Those cases are heard first by administrative judges and then the five-member board, whose decisions can be appealed in federal court.

The growing number of challenges to the labor board make it more likely the issue will reach the U.S. Supreme Court, whose conservative majority has signaled its skepticism of other U.S. agencies’ in-house proceedings, said Seth Goldstein, a lawyer who represents unions in the Amazon and Trader Joe’s cases.

Goldstein said the pending cases also could embolden other employers to refuse to bargain with unions on the belief that courts will strip the NLRB of its enforcement powers.

“I’m very concerned that this is going to cause real problems in collective bargaining for both new and established unions,” said Goldstein, a partner at law firm Julien Mirer Singla and Goldstein in New York.