<i>Nashiri</i>, Conspiracy, and the Ex Post Facto Problem

Notwithstanding the Lawfare love-in, I'm a bit troubled by one of the threads that appeared to emerge from the argument in Nashiri over whether conspiracy is a recognized violation of the laws of war.  Based on Ben's summary, it sounds like both General Martins and Judge Pohl are quite taken with the historical research undertaken by Haridimos Thravalos (and summarized in some detail here). For the reasons that follow, I wonder if they're both missing something: Even assuming for the sake of argument that Thravalos's research calls at least some of Justice Stevens's analysis in Hamdan into question (and, for the record, I'm not sure it does given Hamdan's suggestion that "the precedent must be plain and unambiguous"), how could it possibly help the government's response to Nashiri's Ex Post Facto Clause argument here? Put another way, if the whole point of Thravalos's work is that we've all lost track of this obscure historical precedent, doesn't it necessarily follow that the defendant, as well, could not reasonably have been on notice as to its existence? And as the Supreme Court has repeatedly reiterated, one of the "central concerns" of the Ex Post Facto Clause is "the lack of fair notice and governmental restraint when the legislature increases punishment beyond what was prescribed when the crime was consummated." If no one knew about this example (including the government when it briefed Hamdan before the Supreme Court), how could Nashiri have had "fair notice" thereof? Put another way, even if Thravalos's research helps to put Congress on firmer footing in 2006 in defining "conspiracy" as an offense triable by a military commission prospectively (and, again, I'm not convinced it does, but leave that for another day), how does it help--indeed, doesn't it substantially undermine--the constitutionality of such a prosecution for pre-2006 conduct?