On June 22, 2023, the Eleventh Circuit vacated a decision setting aside an order from the Centers for Disease Control and Prevention requiring masks on public transportation. The court held that the case was moot because the order expired during pendency of the appeal and that Munsingwear vacatur was appropriate. WLF’s brief argued that the Constitution’s structural protections do not disappear during emergencies. Because Congress never gave CDC the power to issue a mask mandate, the order violated separation-of-powers principles. The brief also explained why the order was arbitrary and capricious. Science has proven that mask mandates do not stop the spread of COVID-19.