Editor’s Note: This is the most recent post in a mini-symposium leading up to next week’s en banc oral argument in the DC Circuit in Al Bahlul v. United States. You can check out all of the pieces in the series here.

When the DC Circuit first decided Ali Hamzi al Bahlul’s ongoing appeal en banc last year, they decided that it was not “plain error” to allow his conviction for conspiracy to stand because there was a history of prior military commission convictions for this charge. Since al Bahlul had not objected to the charge at trial, the court held that the issue had not been formally preserved for appeal, failing to qualify for the traditional de novo review accorded to questions of law. They then remanded four constitutional questions, including whether the inclusion of conspiracy — which all sides now concede is not a war crime under international law — in the Military Commissions Acts (MCA) of 2006 and 2009 exceeded congressional authority under the Define and Punish clause and usurped Article III’s commitment of the judicial power to the federal courts. After a three judge panel invalidated the conviction earlier this year, the case is returning for another en banc reconsideration next week.

The parties have been directed to address the standard of review, suggesting potential interest in deciding the case on some basis other than the constitutional legitimacy of committing an offense not recognized as a war crime to a law of war tribunal. I think that doing so would be an injustice to al Bahlul (admittedly not a sympathetic appellant, particularly given recent world events), a departure from the key role of the courts as the protectors of the constitutionally mandated separation of powers, and a decision that will put any future captured American military personnel at risk. I have both written a law review article identifying flaws in the government’s historical arguments in favor of conspiracy charges and submitted an amicus brief advocating reversal.

Few now remember al Bahlul’s original request to be allowed a Yemeni attorney consistent with general international law mandates to the right to counsel of choice, and the practice of virtually all previous law of war trials which have allowed foreign defendants to be represented by co-national counsel at the prosecuting nations’ expense. When that request was denied on the grounds that the MCA limits defense counsel to US nationals, al Bahlul elected to exercise the right of self-representation granted by that same statute. It was only when that right was also denied at the government’s request that he refused to mount any defense other than voicing objection to the commission’s jurisdiction — arguably preserving that fundamental claim.

Military commission jurisdiction has always been subject to strict legal limits, with three distinct historically recognized usages. Commissions have sat: (1) as US military government courts in occupied enemy territory (upheld by Madsen v. Kinsella in 1952); (2) as martial law courts in US territory (prohibited when regular courts are open by Ex parte Milligan in 1866); and (3) as law of war tribunals applying the international legal rules regulating the conduct of hostilities. This final role was endorsed by Ex parte Quirin’s 1942 holding that a law-of-war military commission draws its authority from the Define and Punish clause and that this use constituted “an express exception from Article III.” The previous en banc decision in this case explicitly recognized that “the commission that tried Bahlul is of the third type: a law-of-war military commission.”

Although the MCA alludes to offenses other than war crimes that “have traditionally been triable by military commission,” this is only because many past military commissions have exercised other forms of jurisdiction. When commissions have sat in either the military government or martial law roles, they were substituting for domestic courts and thus enjoyed authority to apply both national and international law. But the Guantánamo commissions, sitting in leased Cuban territory, can only claim law of war authority, and the validity of al Bahlul’s conspiracy conviction depends upon it constituting a war crime in order to bring it within the jurisdiction of that type of tribunal.

The government and some commentators have suggested that al Bahlul could be tried under a “domestic” law of war, apparently inspired by the fact that past military commissions have tried conspiracy charges. But this reliance on domestic precedents as a source of jurisdiction for military commissions is misplaced. In virtually all previous cases where a US military commission tried conspiracy, including most famously the 1865 trial of the Lincoln assassination conspirators, it was sitting in either a martial law or military government role in whole or in part, and thus had a legitimate claim to exercise the domestic law authority that is lacking in the Guantánamo commissions. While it is true that conspiracy was included as the fourth charge in the commission trial reviewed in Quirin, that opinion clearly states that the Court considered only the validity of the first charge, which it found satisfied the requirement for a valid violation of the international law of war necessary to justify the commission’s jurisdiction.

But ultimately, why should we care if a few foreign nationals such as al Bahlul, who as Peter Margulies suggests almost certainly have links to terrorism, are convicted based on questionable jurisdiction? Aside from the fact that we’re supposed to care about the rule of law, we should consider the major risk to US servicepersons that would result from upholding a law of war trial conviction based on historic domestic precedents. This misconstrues the essential nature of the law of war, which has always been understood to be actual international law; indeed, we have long relied upon the law of war as a shield to protect our captured military personnel from non-conforming foreign laws. After the Second World War for example, we convicted Japanese officers who had subjected several of the Doolittle raiders to trial in compliance with Japan’s Enemy Airmen Act for violating the international law of war.

If the United States now decides that it can hold foreign personnel accountable for violating “domestic” law of war rules, other states will be entitled to assert the same authority. Consider the consequences for US personnel captured in a potential future conflict with Iran or China. Are we willing to concede Iran has the ability to try, and even potentially execute, captured Americans based on its ability to find examples of past military punishments in 2,500 years of Persian history? Even more dauntingly, China has more than 4,000 years of historical practice to fall back on. The principle of estoppel would logically bar US objection to such trials. As a matter of both law and respect for our own military personnel, then, this Court should adhere to clear precedent limiting law of war tribunals to prosecuting violations of the international law of war and reverse al Bahlul’s conviction. There is no jurisdictional bar (nor practical risk of double jeopardy) that would prevent the government from charging him with ordinary federal terrorism crimes which have disparate elements from the charges he faced at Guantánamo.