NLRB Board member Gwynne Wilcox has been reinstated, restoring the Board's quorum and enabling it to resume issuing decisions about violations of workers' rights to organize.
Wilcox returned to her post after a federal judge ruled that her termination by President Trump was illegal.
Under the National Labor Relations Act (NLRB), Board members cannot be fired without cause.
"In the ninety years since the NLRB’s founding, the President has never removed a member of the Board," Judge Beryl Howell wrote in her decision. "His attempt to do so here is blatantly illegal, and his constitutional arguments to excuse this illegal act are contrary to Supreme Court precedent and over a century of practice."
The AFL-CIO praised the ruling which is expected to be appealed to the Supreme Court.