In a challenge to an order of the National Labor Relations Board, claiming that the Board lacked a quorum because three of the five Board members had been invalidly appointed, the D. C. Circuit's decision that the appointments fell outside the scope of the Recess Appointments Clause is affirmed, where: 1) the President appointed the three members in question between the January 3 and January 6 pro forma sessions during which no business was transacted; 2) the Recess Appointments Clause empowers the President to fill any existing vacancy during any recess, intra-session (i.e., breaks between formal sessions of the Senate) or inter-session (i.e., breaks in the midst of a formal session), of sufficient length; 3) 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 Recess Appointments Clause; 4) for purposes of the Recess Appointments Clause, the Senate is in session when it says that it is, provided that, under its own rules, it retains the capacity to transact Senate business; 5) under the standard set forth here, the Senate was in session during the pro forma sessions at issue; 6) because the Senate was in session during its pro forma sessions, the President made the recess appointments at issue during a 3-day recess; and 7) 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.