While considerable attention has been paid to the constitutional and treaty questions before the Court in Hamdan, the case begins with a seemingly straightforward question of customary international law: Does conspiracy, the sole charge against Hamdan, violate the law of war? The question is essential because military commissions may only be used to try such violations.

In determining whether conspiracy violates the law of war, its existence as a federal crime prosecutable in a federal court is both insufficient and inapposite. Rather, the answer would seem to turn on two issues. Did Congress define conspiracy as a violation of the law of war pursuant to its Article I, Section 8 power “To define and punish . . . Offences against the Law of Nations”? In the alternative, has a similar result has been accomplished by way of treaty? On both these grounds, there is good reason to believe that the answer is no: Neither the Geneva nor Hague Conventions mention conspiracy, nor did Congress when it defined “war crimes” in 1997. But it is here that Hamdan becomes a strange case indeed.

Lacking clear textual authority to try Hamdan for conspiracy, the Bush Administration argues that authorization derives from customary international law—the so-called “common law” of war—and that statutory and treaty text merely supplement this preexisting body of judge-made law. On its face, this is unremarkable; customary laws of war pre-date both statutes and treaties. What is surprising is that the Bush administration - only two years ago - decried reliance on customary international law in Sosa v. Alvarez Machain.

In Sosa, the Solicitor General was concerned that “the murky nature of customary international law necessitate[s] protracted litigation over the scope and contours of such law, depends on a malleable concept that may vary from one case, or court, to the next . . . [and may] lead to uncertainty and unprincipled decisionmaking . . . .” As a result, courts should not look past the clear language of applicable statutes, because “when Congress focuses its attention on enacting laws that punish or redress violations of the law of nations, it frequently defines the offense or cause of action with precision that is not typically found in customary international law norms.” Anything less would turn customary international law into a “roving license” to create international criminal law, thereby threatening the separation of powers and the Constitution.

Well, something must have changed: The government now cites with approval the very Alien Tort Statute cases they so vigorously objected to in Sosa.

To be sure, elements of Hamdan’s response are a bit unconventional, as well. In particular, he argues that the customary laws of war do not apply to conflicts with non-state actors. This position is in some tension with a human rights movement that has, in the years since Filartiga v. Pena-Irala, argued that customary international law is universal, reaching not only states, but corporations and individuals, as well. Ironically, then, Hamdan likely represents both the most expansive reading of customary international law ever officially taken by the U.S. government and one of the most narrow readings of it ever advanced by the mainstream legal academy.

Of course, the Court may make only the briefest mention of customary international law on its way to the constitutional and treaty questions also at issue. But that would be an unfortunate omission. As the Court made clear in Ex Parte Quirin, the first question a reviewing court must ask is “whether any of the acts charged is an offense against the law of war cognizable before a military tribunal.” Hamdan’s commission cannot stand if conspiracy is not a law of war violation. Moreover, the unconventional positions that both parties have taken provide a perfect opportunity for the Court to provide much needed clarity on the scope and application of customary international law, particularly in times of war. Of course, by doing so the Court would be breaking with its own custom on the topic. But that just may be par for the course in Hamdan.

Ariel N. Lavinbuk is a third-year student at Yale Law School and is the author of a Note published in Volume 114. Though for the past year he has assisted Mr. Hamdan's lead counsel, Neal Katyal, the ideas expressed here are entirely his own.

Preferred Citation: Ariel N. Lavinbuk, Breaking with Custom, Yale L.J. (The Pocket Part), Apr. 2006, http://yalelawjournal.org/forum/breaking-with-custom.