DeArcy Hall agreed with an appeals court that ruled that “the government cannot circumvent application of the warrant requirement simply because queried information is already collected and held by the government,” as the US unsuccessfully tried to argue.

“To hold otherwise would effectively allow law enforcement to amass a repository of communications under Section 702, including those of US persons that can later be searched on demand without limitation,” DeArcy Hall wrote. “While communications of US persons may nonetheless be intercepted, incidentally or inadvertently, it would be paradoxical to permit warrantless searches of the same information that Section 702 is specifically designed to avoid collecting,” she said. And likely equally important, “public interest alone does not justify warrantless querying,” she said.