A federal judge said Gwynne Wilcox must remain at the agency that oversees relations among workers, labor unions and employers, setting up a Supreme Court showdown over presidential powers.

President Donald Trump’s firing of the former chairwoman of the National Labor Relations Board was an “illegal act,” a federal judge ruled Thursday, overturning her ousting in a decision that was highly critical of Trump’s “intent on pushing the bounds of his office.

Gwynne Wilcox was the first National Labor Relations Board member ever fired. A judge said Trump does not have the power to fire board members 'at will.'