President Obama used his recess appointment power in an unprecedented way to bring the National Labor Relations Board back to full strength. On Jan. 4, he announced the recess appointments of Democrats Sharon Block, deputy secretary for congressional affairs at the Labor Department, and Richard Griffin, general counsel for the International Union of Operating Engineers. He also named Republican Terence Flynn, counsel to board member Brian Hayes.

Congressional Republicans had vowed to block recess appointments by convening brief, pro forma sessions every third day whenever Congress was not meeting, based on precedent that recess appointments are only allowed after Congress is shut down for three days. White House lawyers concluded the pro forma sessions were a sham the president could ignore, setting up a likely court fight.

“Although the U.S. Constitution doesn’t specifically reference the length of the recess in connection with the president’s authority to make recess appointments, in 1993 the Department of Justice took the position that Congress should be in recess for more than three days, and this practice typically has been followed,” says Barnes & Thornburg Partner Teresa Jakubowski. “A legal challenge could well follow.”