Fired Democratic National Labor Relations Board member Gwynne Wilcox sued President Donald Trump on Wednesday, arguing her removal violates a 90-year-old U.S. Supreme Court precedent that limits the president’s power to terminate appointees at independent multimember agencies.

“The President’s unprecedented removal of Ms. Wilcox defies 90 years of Supreme Court precedent that has ensured the independence of critical government agencies," Wilcox' attorney Deepak Gupta said in a statement Wednesday.