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.

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.

A federal judge in Washington ordered the Trump administration to reinstate a member of the National Labor Relations Board on Thursday, finding her firing without cause violated federal law. Trump officials in January fired Gwynne Wilcox,