The state secrets privilege is a common-law evidentiary privilege that allows the Executive to withhold certain information from civil discovery if it believes disclosure would harm the national security or foreign policy of the United States. The privilege is absolute. If a court accepts the Executive’s assertion that the subject evidence could reasonably harm the nation’s security, the information may not be disclosed regardless how great the need of the party seeking discovery is said to be. In addition to sanctioning sensitive evidence or information in its possession, the Executive can apply the privilege to protect against disclosure of the nation’s intelligence gathering sources, methods, and capabilities, and against disruption of diplomatic relations with foreign governments....