With the legitimacy of more than 500 labor-management decisions at stake, the U.S. Supreme Court on Tuesday appeared divided over whether the vacancy-hobbled National Labor Relations Board can operate with only two of its five board members.

“We have to decide whether it is OK for two members to set the most major policies or whether they can’t conduct even the simplest adjudications,” said Justice Stephen Breyer during arguments in New Process Steel L.P. v. National Labor Relations Board.