In a unanimous decision, the Supreme Court ruled Thursday that three of President Obama's recess appointments to the National Labor Relations Board were invalid because they occurred during a “pro forma” session of the Senate.

While rebuking Obama, who had sought a broader power to fill vacancies due to Senate "intransigence," the court’s majority did not adopt the more restrictive interpretation of the recess appointment power that would have limited its use to vacancies occurring only during the annual break between Senate sessions.

"Because the Senate was in session during its pro forma sessions, the President made the recess appointments at issue during a 3-day recess. Three days is too short a time to bring recess within the scope of the Clause so the President lacked the authority to make those appointments," the court ruled.

The ruling was a blow to Big Labor, which will now see more than a year's worth of decisions by the NLRB retroactively invalidated, though the Supreme Court case had already left them in limbo anyway.

The opinion was written by Justice Stephen Breyer, and he was joined by Justices Anthony Kennedy, Ruth Bader Ginsburg, Sonia Sotomayor and Elena Kagan. It held that the Senate is in session when the Senate says it is in session, as when Obama made his recess appointments.

Justice Antonin Scalia filed a separate opinion concurring with the overall judgment that the appointments were invalid, but arguing that a more restrictive view of the president's recess appointment power was more consistent with the U.S. Constitution.

Scalia was joined by Chief Justice John Roberts, as well as Justices Clarence Thomas and Samuel Alito.

The case involved three presidential appointments to the NLRB. Obama first nominated them on Dec. 13, 2011, then appointed them onto the board Jan. 4, 2012, just three weeks later. The Senate was technically in recess at the time, holding pro-forma sessions. The White House nevertheless decided this did not count as an actual session and so went ahead with the appointments.

Contrary to the White House's claim that Senate gridlock necessitated the move, the Senate never actually filibustered the three nominees. They never even had time to hold hearings on them.

In the decision the majority stated: "The [Constitution's] Adjournments clause ... reflects the fact that that a 3-day break is not a significant interruption of legislative business. A senate recess that is so short that it does not require the consent of the House under that Clause is not long enough to trigger the President's recess-appointment power."

In effect, the majority held that while the president does have clear a recess appointment power, Obama overstepped that power by trying to argue that the White House, not just the Senate, could decided when it was and was not in a recess.

Scalia, while concurring that the appointments were invalid, scolded the majority for not reining in the president's authority further.

"The recess-appointment power is an anachronism," he said, noting that modern communications and travel meant that "the Senate now is effectively always available on short notice to consider the president's nominations."

The fact that political friction between the branches might prevent some vacancies from being filled was not an issue for the court to resolve, he said.