This monograph offers a neo-classically republican perspective on a perennial problem of civilian/military relations: limitations on military officers’ obligation to obey civilian authorities. All commentators agree that military officers are generally obliged—morally, professionally, and legally—to obey civilian orders, even as they agree that this rule of obedience must admit of exceptions. Commentators tend to differ, however, on the basis and breadth of these exceptions. Following Samuel Huntington’s classic analysis in The Soldier and the State, this monograph shows that disagreement about the breadth of the exceptions tends to assume that their bases—moral, professional, and legal—are incommensurable. It suggests, to the contrary, that all defensible exceptions to the rule of military obedience, like that rule itself, derive from a single neo-classical, Huntingtonian standard, binding on civilian authorities and military officers alike: the common good. This perspective promises significantly to reduce the range of disagreement over the limits of military obedience both in theory and in practice.