The Supreme Court has sided with Congress in a dispute over presidential recess appointments.
The constitution allows a president to fill temporary appointments during a recess without congressional approval.
Recently lawmakers have attempted to prevent certain appointment by never technically shutting down the Senate.
The justices ruled unanimously that three of president Obama’s appointments to the National Labor Relations Board were invalid because they were made during one of those periods "too short" to be considered a recess.
The ruling could invalidate hundreds of decisions by the NLRB.