S.C. Code Ann. § 25-1-1850

Whenever, by reason of unlawful obstructions, combinations or assemblages of persons or rebellion against the authority of the government of this State, it shall become impracticable, in the judgment of the Governor to enforce by the ordinary course of judicial proceedings the laws of the State within any county or counties of the State, the Governor may call forth the National Guard of the State or such parts thereof as he may deem necessary to enforce the faithful execution of the laws or to suppress such rebellion.