For those not deeply versed in US federal regulations: Part 4a of Title 15 of the Code of Federal Regulations (CFR), which covers the "Classification, Declassification, and Public Availability of National Security Information" for the National Security Agency (NSA).
Not entirely sure, but I thought they were talking about the 4th amendment, which also is relevant. It prevents the government from spying on Americans without a warrant. The NSA works around it so openly by buying the spy data from third parties, and saying the 4th Amendment doesn’t apply since they didn’t collect the data themselves, so it’s fine. It’s a giant middle finger to the Constitution of the US.
<https://www.ecfr.gov/current/title-15/subtitle-A/part-4a?toc...>