WASHINGTON—A member of the National Labor Relations Board fired by President Trump sued him Wednesday, setting up a high-stakes battle over whether federal law limiting the president’s power to remove top executive-branch officials is constitutional.

The NLRB has come under fire from companies including Amazon and Elon Musk's SpaceX, who have argued that the labor board's structure is unconstitutional.

Gwynne Wilcox, a Democratic member of the National Labor Relations Board (NLRB) fired by President Trump, sued him Wednesday over the ouster. Wilcox’s attorneys claim Trump’s firing was a “blatant violation” of NLRB members’ removal protections contained within the National Labor Relations Act (NLRA).