Mississippi Code Title 33. Military Affairs § 33-7-301

(1) The Governor shall have power in case of invasion, disaster, insurrection, riot, breach of the peace, or combination to oppose the enforcement of the law by force or violence, or imminent danger thereof or other grave emergency, to order into the active service of the state for such period, to such extent and in such manner as he may deem necessary, all or any part of the organized militia. Such power shall include the power to order the organized militia or any part thereof to function under the operational control of the United States army, navy, or air force commander in charge of the defense of any area within the state which is invaded or attacked or is or may be threatened with invasion or attack.

(2) Whenever any circuit judge of a county, sheriff, or mayor of a municipality, whose authority shall rank in the order named, shall apprehend the outbreak of insurrection, riot, breach of the peace, or combination to oppose the enforcement of the law by force or violence within the jurisdiction of which such officer is by law the conservator of the peace, or in the event of disaster or other grave emergency, it shall forthwith become the duty of the circuit judge, sheriff or mayor, when it appears that such unlawful combination or disaster has progressed beyond the control of the civil authorities, to notify the Governor, and the Governor may then, in his discretion, if he deems the apprehension well-founded or the disaster or emergency of sufficient magnitude, order into the active service of the state, for such period, to such extent, and in such manner as he may deem necessary, all or any part of the organized militia.

(3) When the Governor orders into the active service of the state all or any portion of the organized militia as herein provided, he shall declare a state of emergency in such locality and it shall be the duty of the Governor to confirm such declaration and order in writing which shall state the area into which said force of the organized militia has been ordered.