Last year, Noel Canning asked the Supreme Court to determine the validity of President Obama’s recess appointments to the National Labor Relations Board. Those appointments went through during a very short recess that occurred between two pro forma sessions of the United States Senate. Canning argued that the 3 day recess was not long enough to trigger the Recess Appointments Clause of the Constitution, which normally gives the President the power to “fill up all Vacancies that may happen during the recess of the Senate.”

In today’s opinion, the Supreme Court unanimously agreed with Canning, saying that the Recess Appointments Clause empowers the President to fill any existing vacancy during any recess–of sufficient length. Unfortunately for the Obama Administration and its appointees, the Constitution does not specify how long a recess must be in order to trigger the Clause:

The Adjournments Clause, Art. I, §5, cl. 4, reflects the fact 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. Moreover, the Court has not found a single example of a recess ap-pointment made during an intra-session recess that was shorter than 10 days. There are a few examples of inter-session recess appointments made during recesses of less than 10 days, but these are anomalies. In light of historical practice, a recess of more than 3 days but less than 10 days is presumptively too short to fall within the Clause.

Interestingly (and to the great chagrin of Justice Scalia, who joined the judgment but wrote a separate concurring opinion,) the Court allowed historical practice and the longstanding “practice of the government” to influence its reasoning:

…in interpreting the Clause, the Court puts significant weight upon historical practice. The longstanding “practice of the government,” McCulloch v. Maryland, 4 Wheat. 316, 401, can inform this Court’s determination of “what the law is” in a separation of powers case, Marbury v. Madison, 1 Cranch 137, 176. There is a great deal of history to consider here, for Presidents have made recess appointments since the beginning of the Republic. Their frequency suggests that the Senate and President have recognized that such appointments can be both necessary and appropriate in certain circumstances. The Court, in interpreting the Clause for the first time, must hesitate to upset the compromises and working arrangements that the elected branches of Government themselves have reached.

Thus, the death blow:

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 a recess within the scope of the Clause, so the President lacked the authority to make those appointments.

This decision is narrow, but its finer points don’t bode well for the public employee parties in Harris v. Quinn. It also gives hope to Senate and House conservatives looking for a way to block future appointments that fall within the scope of the Recess Appointments Clause.

You can read the full opinion here.