10 U.S.C. § 331 : US Code - Section 331: Federal aid for State governments

Search 10 U.S.C. § 331 : US Code - Section 331: Federal aid for State governments

Whenever there is an insurrections in any State against its
government, the President may, upon the request of its legislature
or of its governor if the legislature cannot be convened, call into
Federal service such of the militia of the other States, in the
number requested by that State, and use such of the armed forces,
as he considers necessary to suppress the insurrection.