Whenever any portion of the militia of the State is on duty under or pursuant to orders of the Governor or whenever any part of the militia is ordered to assemble for state duty, the systems, precedents, and procedures established in the Uniform Code of Military Justice for the governing of armed forces of the United States, so far as applicable and not in conflict with any rule or regulation herein prescribed, is considered in full force and regarded as a part of this chapter until such forces are duly relieved from such duty. Nothing in this section is construed as relinquishing the state's authority and jurisdiction in such matters. No punishment under this section extending to the taking of life shall in any case be inflicted except in time of actual war, invasion, or insurrection declared to exist by proclamation of the President of the United States or the Governor of this State, and then only after the approval of such sentence by the Governor. The Governor shall review the findings of all general courts-martial convened during such situations hereinabove recited.