Discretion, Delegation, and Defining in the Constitution's Law of Nations Clause

ABSTRACT-Never in the nation's history has the scope and meaning of Congress's power to "define and punish . . . Offences against the Law of Nations" mattered as much. The once-obscure power has in recent years been exercised in broad and controversial ways, ranging from the Alien Tort Statute (ATS) to military commission trials in Guantanamo Bay. Yet it has not yet been recognized that these issues both involve the Offenses Clause and indeed raise common constitutional questions. First, can Congress "define" offenses that clearly already exist in international law, or does it have discretion to codify debatable or even nonexistent international law norms? Second, what happens to this discretion when it delegates the power to a coordinate branch?This Article shows that the Offenses Clause allows Congress only to "define"-to specify the elements and incidents of-offenses already created by customary international law. It does not allow Congress to create entirely new offenses independent of preexisting international law. At the same time, the Framers understood international law to be vague and intertwined with foreign policy considerations. Thus, courts reviewing congressional definitions should give them considerable deference. Moreover, whatever discretion Congress has in defining offenses disappears when it broadly delegates that power to another branch, as it has in the ATS. The Supreme Court suggested a similar standard for ATS causes of action in Sosa v. Alvarez-Machain. Appreciating the role of delegation in the ATS shows that the limits on offenses that can be litigated under the statute have a constitutional dimension.The Article develops the original understanding of the Offenses Clause-particularly important given the lack of any judicial decisions on it in the nation's first century. It draws on previously unexplored sources, such as early cases about the meaning of the "define" power in the cognate context of "piracy and felonies," legislation by early Congresses, and discussions by Framers like Madison and others.INTRODUCTIONNever in the nation's history-at least not since the Neutrality and Alien Acts debacles of the 1790s-has the scope and meaning of Congress's power to "define and punish . . . Offences against the Law of Nations"1 mattered as much. The once-obscure and seldom-used power2 has in recent years been exercised in controversial ways, ranging from civil human rights litigation under the Alien Tort Statute (ATS), to military commission trials in Guantanamo Bay, to the historic prosecutions being conducted against Somali pirates in federal courts. Yet it has not been recognized that these issues all raise similar constitutional questions under the Offenses Clause.This Article sketches the limits of Congress's power to define offenses. Furthermore, it examines the reach of the power when Congress delegates authority to define offenses to other branches. The former analysis has significance for the current military commission litigation, where the defendants argue that the crimes they are charged with fall outside international law and thus Congress's define power. The delegation issue has even greater implications for the ATS. In the statute's interpretation by the Supreme Court in Sosa v. Alvarez-Machain, the power of federal courts to define international law causes of action themselves was the central issue.3 The Supreme Court is poised to significantly revisit the ATS in Kiobel v. Royal Dutch Petroleum Co., an effort that should be informed by an awareness of the constitutional backdrop to the statute.4The Offenses Clause's new relevance comes in the wake of unprecedented, yet unheralded, developments in Offenses Clause jurisprudence. Hamdan v. Rumsfeld5 was the first case ever to find the government exceeded its Offenses Clause powers.6 This historic aspect of the case has been overlooked (including by the Supreme Court itself), perhaps because the case was mostly noted for its more newsworthy rebuke of the Bush Administration's Guantanamo policies. …