No form of war is more closely tied to law than counterinsurgency. Counterinsurgency is, at its core, a contest for “legitimacy,” and the legitimacy of a modern government is inherently tied to its ability to bring about the rule of law. Although counterinsurgency doctrine is consumed with building both legitimacy and the rule of law, it lacks a clear understanding of how law contributes to legitimacy. Moreover, law is useful to counterinsurgents in a variety of ways; more disturbing is the possibility that the use of law as a means to conducting counterinsurgency is not only counterproductive to building legitimacy but may actually undermine the authority of the law itself. Recognizing the complex relationship between law and legitimacy requires counterinsurgents to temper their rush to law as a means of war with consideration of the second- and third-order effects generated by introducing a complex and morally contingent a concept like law as a means to obtaining operational advantage in armed conflict.
The paper describes the relationship between law and legitimacy as suggested by U.S. counterinsurgency doctrine and addresses how the “rule of law” can actually build legitimacy. Building legitimacy is not the only way law is used in counterinsurgency, and so the paper describes the four distinct ways law is used in counterinsurgency and how those various uses related to legitimacy and thereby to the authority of the law. A complete understanding of how laws is used by counterinsurgents reveals that the many uses of law in counterinsurgency fall along a continuum of legitimacy. Keeping that continuum in mind has implications for practice, which are discussed in the final section of the paper.