The vacancy-plagued National Labor Relations Board did not have authority to issue nearly 600 decisions in the last two years with only two board members, the U.S. Supreme Court ruled on Thursday.

In New Process Steel v. National Labor Relations Board, a 5-4 Court upended the NLRB’s attempt, dating back to 2007, to continue functioning when it foresaw that its membership was in imminent danger of dropping from four to two.