Here's commentary about a recently leaked memo by General McChrystal that includes a discussion of the responsibilities of military leaders in a civilian controlled military:
The principle of civilian control means that once the competent civilian authorities have made a binding decision, military leaders are obligated to support it and carry it out. If they cannot in good conscience do so, they should resign. The principle does not mean that military leaders are barred from publicly expressing their best judgment as to the strategy and tactics best suited to the problem at hand before the civilian authorities have made their decision.
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