The case is Hamdan v. United States (D.C. Cir. Oct. 16, 2012), and it’s noteworthy that the panel is quite conservative — the opinion is written by Judge Brett Kavanaugh, joined almost in its entirety by Judges David Sentelle and Douglas Ginsburg. The conclusion:
Because we read the Military Commissions Act not to sanction retroactive punishment for new crimes [in part to avoid possible Ex Post Facto clause problems -EV], and because material support for terrorism was not a pre-existing war crime under 10 U.S.C. § 821, Hamdan’s conviction for material support for terrorism cannot stand.
And here’s an amusing footnote from the majority, responding to Judge Ginsburg’s concurrence (which suggests that Hamdan’s appeal ought to be seen as moot, because he has served out his sentence and is now in Yemen):
In his concurring opinion, Judge Ginsburg calls for a change to existing Supreme Court mootness doctrine. In doing so, Judge Ginsburg suggests that Hamdan is in Yemen and has little chance of landing in future trouble in the U.S. legal system. Maybe. Maybe not.