Thravalos on Hamdan, Conspiracy, and History (Updated)

by Kevin Jon Heller

Lawfare has published a very interesting guest post by Haridimos Thravalos on whether conspiracy is a war crime.  The whole thing is worth a read; here is the intro:

In June 2006, the U.S. Supreme Court struck down President George W. Bush’s use of military commissions to try suspected members of al-Qaeda in Hamdan v. Rumsfeld, 548 U.S. 557 (2006). In Hamdan, a plurality of the Court also concluded that conspiracy was “not a stand-alone offense against the law of war” triable by “law-of-war military commission.” See Hamdan, 548 at 608.

The issue of whether conspiracy is triable by military commission has become suddenly relevant again: It is today pending before the U.S. Court of Appeals for the District of Columbia Circuit in the case of Ali Hamza Suliman Ahmad Al Bahlul v. United States and may be headed back to the Supreme Court. In Al Bahul, one of the issues to be decided is whether Congress has the constitutional power in the Military Commissions Act of 2009, 10 U.S.C. §§ 948a-950t (2006 & Supp. IV 2010), to authorize trial of the offense of conspiracy by military commission. Petitioner Al Bahlul contends that “[t]here is an extensive and unanimous history of rejecting conspiracy to commit war crimes.” Brief of Petitioner at 19, Al Bahlul v. United States, No. 11-1324 (D.C. Cir. Mar. 9, 2012). He bases his conclusion, with respect to domestic precedents, solely upon the reasoning adopted by the Hamdan plurality. So the plurality’s use of history has immediate consequences for the vitality of military commissions now and in the future.

It is the purpose of this brief memorandum to demonstrate that the Hamdan plurality’s conclusions of law with respect to conspiracy were based on bad history–either incomplete or erroneous facts.

There is, however, a basic problem with Thravalos’ argument.  He claims that “[t]he Hamdan plurality found that conspiracy was not a violation of the law of war under domestic precedents for three reasons” (emphasis mine).  But the Hamdan plurality was not concerned with whether “domestic precedents” — i.e., US practice — supported viewing conspiracy as a war crime; it was interested in determining whether conspiracy was a war crime under international law, as the following passages from the decision make clear:

At a minimum, the Government must make a substantial showing that the crime for which it seeks to try a defendant by military commission is acknowledged to be an offense against the law of war. That burden is far from satisfied here. The crime of “conspiracy” has rarely if ever been tried as such in this country by any law-of-war military commission not exercising some other form of jurisdiction and does not appear in either the Geneva Conventions or the Hague Conventions—the major treaties on the law of war.


Finally, international sources confirm that the crime charged here is not a recognized violation of the law of war. As observed above, none of the major treaties governing the law of war identifies conspiracy as a violation thereof. And the only “conspiracy” crimes that have been recognized by international war crimes tribunals (whose jurisdiction often extends beyond war crimes proper to crimes against humanity and crimes against the peace) are conspiracy to commit genocide and common plan to wage aggressive war, which is a crime against the peace and requires for its commission actual participation in a “concrete plan to wage war.” The International Military Tribunal at Nuremberg, over the prosecution’s objections, pointedly refused to recognize as a violation of the law of war conspiracy to commit war crimes, and convicted only Hitler’s most senior associates of conspiracy to wage aggressive war. As one prominent figure from the Nuremberg trials has explained, members of the Tribunal objected to recognition of conspiracy as a violation of the law of war on the ground that “[t]he Anglo-American concept of conspiracy was not part of European legal systems and arguably not an element of the internationally recognized laws of war.”

These references to international law would have been irrelevant if the Hamdan plurality had been trying to determine whether the US “common law of war” considered conspiracy to be a war crime.  But, again, that wasn’t the question — just as it wasn’t the question for the Quirin court, as Steve Vladeck has pointed out (emphasis in original):

The question, of course, is what Quirin meant by “offenses committed by enemy belligerents against the law of war.” But critically, in ascertaining whether the charged offenses qualified as such, the Quirin Court looked to the international law of war, and not to the “U.S. common law of war” that the government now invokes in Hamdan. Indeed, Chief Justice Stone specifically tied Congress’s authority to create the jurisdiction at issue in Quirin to the Define and Punish Clause (which incorporates international law), not Congress’s various “war-making” powers (which would presumably be the indirect source of such common law).

Thravalos does not address the Hamdan plurality’s discussion of international sources, nor does he acknowledge that the plurality viewed US precedent simply as one kind of evidence (insufficient in and of itself) of whether international law viewed conspiracy as a war crime.  So even if he is correct that the plurality misdescribed US practice — and we should not forget that the American-run Nuremberg Military Tribunals specifically rejected the idea that conspiracy was a war crime — his argument in no way undermines the plurality’s conclusion.  The question was whether conspiracy is a war crime under international law.  The answer, as the plurality correctly held, is no.

UPDATE: Ben Wittes offers the following comment on my post:

[W]hile I agree with Kevin that the Supreme Court was ultimately concerned with the international law of war, not some U.S. common law of war, a reasonable reading of the opinion suggests that the court was particularly concerned with the contemporary and historical U.S. understanding of the place of conspiracy in that body of law. To the extent the court got that issue wrong–as it seems to have done–that simply has to matter.

I did not mean to imply that Thravalos’s point does not matter.  If his history is right — and he certainly seems to know what he’s talking about — his post provides an important corrective to how we understand US practice regarding the prosecution of conspiracy in military commissions.  My point was that Thravalos fails to establish what seems to me to be his central claim: namely, that in light of the evidence he musters, “there is ‘a substantial showing’ that ‘conspiracy to violate the law of war is a violation of the law of war, thus satisfying the Hamdan plurality’s test for lawfulness.”  As I noted — and Ben apparently agrees — Hamdan was concerned with international law, not the US common law of war.  So no matter how strong US practice might be, it cannot by itself satisfy Hamdan‘s “substantial showing” test.

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  1. […] var addthis_config = {"data_track_clickback":false};Over at Opinio Juris, Kevin Jon Heller offers the following objection to Haridimos Thravalos’s guest post last night on Hamdan, conspiracy, and history: There is, […]

  2. […] got its history wrong concerning whether conspiracy could be tried as a war crime.  See also this response from Kevin Jon Heller and Wittes’ […]