(1) Except as provided in Subsection (2) of this Section, conduct is justifiable when it is required or authorized by:

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    (d) the law governing the armed services or the lawful conduct of war;  . . .

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  (2) The other sections of this Article apply to:

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    (b) the use of deadly force for any purpose, unless the use of such force is otherwise expressly authorized by law or occurs in the lawful conduct of war.

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