Amazon alleged in a legal filing published Friday morning that the National Labor Relations Board (NLRB) is unconstitutional. SpaceX and Trader Joe’s — companies that, like Amazon, have repeatedly faced labor law violations from the federal agency — have recently made similar attacks that threaten national worker protections.

This is just Amazon’s latest attempt to block union organizing in its fulfillment centers. But this time, these companies aren’t just limiting the rights of their own workers. If these threats against the NLRB keep moving forward, American workers could lose workplace protections that they’ve had for almost a century.