Whenever any portion of the organized militia is called into active service to execute the laws, engage in disaster relief, suppress actual or prevent threatened insurrection or repel invasion, the commanding officer shall use his own discretion with respect to the propriety of attacking or firing upon any mob or unlawful assembly. His honest and reasonable judgment in the exercise of his duty shall be full protection, civilly and criminally, for any act or acts done while on duty; and no member of the organized militia in the active service of the state shall be liable civilly or criminally for any act or acts done by him in the performance of his duty.
§ 41.700, RSMo