President Obama's three recess appointments to the National Labor Relations Board were challenged after the Board ruled against a bottling company. The Senate had been holding brief pro forma sessions every three days precisely to prevent recess appointments. Justice Breyer's opinion accepted broad historical readings of the clause — recesses include intra-session breaks and vacancies need not first arise during the recess — but drew a hard line: a recess must generally be at least ten days for the appointment power to activate, and the Senate itself decides when it is in session. Because the pro forma sessions counted, the disputed appointments were invalid. Noel Canning is the most important structural-Constitution decision of the 2010s and dramatically curtailed a workaround Presidents of both parties had used for decades.