The Hamdan Case and the Application of a Municipal Offence: The Common Law Origins of ‘Murder in Violation of the Law of War’

This article examines the legal origins of ‘murder in violation of the law of war’, an offence defined in the US Military Commissions Act (MCA) and resorted to in the case against Salim Ahmed Hamdan. Hamdan was acquitted of conspiring to commit this offence based in part on a questionable legal instruction. The acquittal may have been proper under a correct view of the law. Nevertheless, the specific context in which this offence was alleged, combined with the judge's instruction, highlights key aspects of the US approach to the prosecution of unprivileged fighters for a ‘law of war violation’. This approach, which is substantially represented by the US Supreme Court's judgment in ex parte Quirin, has been criticized by International Humanitarian Law (IHL) scholars as an erroneous view of customary IHL. However, close analysis of the legal and historical context in which this approach developed reveals that ‘murder in violation of the law of war’ is a municipal US offence that represents an English common law implementation of the law of nations. This article explains why reading this offence to incorporate IHL war crimes, as Hamdan's judge did, is inappropriate in the context of the MCA and Hamdan's case. It then demonstrates that the authorities relied upon by the Quirin Court, the Lieber Code and a treatise by authoritative US military law commentator, William Winthrop, understood punishment for law of war violations to be permitted by the law of nations but imposed under municipal law. Thus, ‘murder in violation of the law of war’ is properly viewed as a municipal, common law offence punishing unprivileged fighters. In future studies the author will address the appropriateness of prescribing and enforcing this municipal offence in extraterritorial armed conflict.