Former NLRB member Gwynne Wilcox has sued over her unprecedented removal from the board by President Donald Trump, in a case that could test the limits of presidential authority over independent agencies.

Gwynne Wilcox alleged that President Trump exceeded his authority and broke with nine decades of precedent in ousting her from the agency that oversees unions and workers’ rights.

An ex-member of the National Labor Relations Board, whom President Trump fired last month, filed a lawsuit Wednesday challenging her dismissal and asking a federal court to reinstate her to the board.