S.C. Code § 25-1-1880
In the event of insurrection, rebellion, invasion, tumult, riot, resistance to law or process or breach of the peace occurring in the vicinity of the station of any organization of the National Guard of South Carolina, the senior commanding officer of that station, whenever the exigencies of the situation are such as to render it impossible first to communicate with the Governor, or Adjutant General, may, upon request in writing by the sheriff of the county involved or an officer acting in his stead stating the facts and the nature of the service desired, order out the organization at that station or such portion thereof as he shall deem necessary and cause it to perform such duty as the circumstances shall require. In any such case such commanding officer shall immediately report what he has done and all of the circumstances of the case to the Governor and it shall be deemed that the action was taken by order of the Governor.
S.C. Code § 25-1-1880