Raff already outlined the issues the en banc D.C. Circuit (minus Judge Srinivasan) will confront in tomorrow's oral argument in al Bahlul v. United States, and I have very little of substance to add to Jen Daskal's thorough analysis over at Just Security, or Marty Lederman's addendum thereto. Instead, I thought I'd take a slightly different tack, and make what's almost certainly a foolhardy attempt to handicap the outcome...
To my mind, everything turns on why the D.C. Circuit decided to rehear this case en banc. Assuming that Judge Kavanaugh still believes what he wrote for the three-judge panel in Hamdan II, it seems to me that there are three possible explanations for the grant, each of which portends a slightly different outcome:
1. Disagreement With Judge Kavanaugh's Retroactivity Analysis
Explanation: By far, the most likely reason why the D.C. Circuit decided to rehear al Bahlul en banc is because some combination of the other six active judges disagree with Judge Kavanaugh's interpretation of the Military Commissions Act of 2006 in Hamdan II as not intending to apply the newly defined offenses (including conspiracy, the central charge at issue in tomorrow's argument) retroactively. For Judge Kavanaugh, this reasoning allowed the Hamdan II panel to sidestep the constitutional question of whether the MCA, if so applied, violates the Ex Post Facto Clause. Given that the only additional questions on which the en banc court asked for briefing involve the applicability of the Ex Post Facto Clause--and given that, in my own view, the MCA was meant to apply retroactively--this seems the most likely explanation for why the D.C. Circuit granted the government's petition.
Outcome: If this is why the Court of Appeals went en banc, it does not bode well for the government, which would need to convince four of the six remaining judges (other than Kavanaugh) either that (1) conspiracy was triable by military commissions prior to the enactment of the MCA (which would moot the retroactivity issue, but which runs directly counter to Justice Stevens' opinion for a four-Justice plurality in Hamdan I); or (2) even if it wasn't, the MCA both (a) applies retroactively; and (b) does not violate the Ex Post Facto Clause as so applied. Even then, there's still the lurking Article III question Marty flagged in his Just Security post... Put simply, the government would need at least two votes from the quartet of Chief Judge Garland and Judges Griffith, Rogers, and Tatel (and that's assuming that the government is likely to have Judges Henderson and Brown on its side--hardly a foregone conclusion). Such a vote breakdown strikes me as a long-shot, at best. Moreover, even if there is disagreement among the D.C. Circuit's judges about whether the MCA simply doesn't operate retroactively, or is unconstitutional to the extent that it does (so perhaps no majority on the en banc court), the bottom line would be the same under either rationale: no more military commission trials for pre-2006 inchoate offenses.
2. Disagreement With Judge Kavanaugh's Analysis of Article 21
Explanation: Another possibility is that at least four of the six remaining active judges on the D.C. Circuit disagree with Judge Kavanaugh's analysis of Article 21 of the UCMJ as only authorizing military commission trials for violations of the international laws of war. (If Article 21 also encompasses violations of the "U.S. common law of war," and if conspiracy so qualifies, then there's arguably no ex post facto issue inasmuch as Bahlul could have been tried by a military commission for conspiracy at the time of the conduct giving rise to his prosecution. By this logic, the MCA is simply codifying what was already available practice under the pre-2006 UCMJ.
Outcome: If this is why the D.C. Circuit went en banc, then it does not bode well for al Bahlul, for it would suggest that the government would only have to show that conspiracy was a recognized violation of the "U.S. common law of war" circa 2001--a claim that I don't buy, but that is arguably a closer call than whether the MCA violates the Ex Post Facto Clause. At the same time, this strikes me as a far less likely explanation for why the Court of Appeals went en banc, for it would not just be disagreement with Judge Kavanaugh's analysis in Hamdan II, but also the analysis of the Hamdan I plurality--which held both that Article 21 only encompasses well-established international war crimes and that conspiracy was not such a well-established offense in 2001. Again, there may be some D.C. Circuit judges who are perfectly happy to disagree with Justice Stevens' opinion in Hamdan I, but I have a very hard time counting to four.
3. Because the Government Asked...
Explanation: The last possibility that I can come up with is that the D.C. Circuit granted the government's petition because the government asked it to--not because of any pre-set agreement or disagreement with Judge Kavanaugh's analysis in Hamdan II. As I've noted in other contexts, there's just something different about granting discretionary review in a high-profile national security case when it's the government that's invoking it, and so the en banc grant could be nothing more than giving the government the benefit of the doubt and ensuring that such an important issue is resolved by the en banc court.
Outcome: This is the hardest explanation to handicap, because it presupposes a grant without regard to any view of the merits. I think we end up back in the same place, though--with the government still needing to find four judges other than Kavanaugh to agree with one of the two dominant strands of its argument. Two, quite possibly. Three, maybe. Four? Therein lies the rub.