# Defense Support of Civil Authorities **Status: stub — expand.** **DSCA. Governed by DoD Directive 3025.18 (December 29, 2010, Change 2 of March 19, 2018) and DoD Instruction 3025.21.** The framework under which federal military forces support civilian agencies inside the United States — disaster response, special-event security, and law-enforcement support that stops short of direct participation. Two authorities inside it matter for deployment questions: - **Immediate Response Authority** (¶ 4.i) — a local DoD commander may act on a civil authority's request "under imminently serious conditions" to save lives, prevent human suffering, or mitigate great property damage, but explicitly **not** in ways "regulatory, prescriptive, proscriptive, or compulsory" toward civilians. Must be reassessed within 72 hours. - **Emergency Authority** (¶ 4.k) — the far broader claim: a federal commander may act to quell large-scale unexpected civil disturbances where prior presidential authorization is impossible and local authorities cannot control the situation, **or** where authorities "are unable or decline to provide adequate protection for Federal property or Federal governmental functions." That second clause is the regulatory ancestor of the "protective power" theory the government advanced and lost in the 2025–26 federalization litigation. Statutory support runs through 10 U.S.C. §§ 271–284, with § 275 barring direct participation in searches, seizures, and arrests. ## See also - [[National Guard Federalization Flow]] · [[National Guard]] · [[Posse Comitatus Act]] · [[Insurrection Act]]