Exemption 3 of the Freedom of Information Act states that a federal agency can withhold a document that has already been deemed non-disclosable by a different statute. That exemption is often used by agencies that are involved in traditional national security practices and the controversial modern techniques of pervasive electronic surveillance, as justification for keeping information on those practices secret. This article argues that Exemption 3 has inadvertently made the security and surveillance establishment more secretive, creating a nearly irrebuttable presumption that documents must not be disclosed to citizens or journalists. Exemption 3 jurisprudence has allowed precedents on the secrecy of old-school surveillance techniques to be applied to the far more pervasive techniques exercised by security agencies in the modern era.