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.

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).

Gwynne Wilcox’s lawsuit is the first to challenge the president’s ouster of several members of independent boards — moves that appear to contravene a 1935 Supreme Court ruling.

Gwynne Wilcox, who was appointed to the board by former President Joe Biden, said in a lawsuit filed in the U.S. District Court for the District of Columbia that her firing last week violated U.S. law.

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.