As Wells noted, the Guantánamo Military Commission Convening Authority has declined to adopt Chief Prosecutor Brig. Gen. Mark Martins's recommendation to withdraw the conspiracy charges against Khalid Sheikh Mohammed and the other 9/11 defendants. Withdrawal, which can be done for any reason and at any time prior to trial findings being announced, would normally lead to the dismissal of charges. However, the withdrawn charges could potentially have been reinstated in this or a later military commission, if, for instance, the Supreme Court ultimately found that conspiracy was triable by military commissions and thus put the charges on firm legal footing. Mil. Comm'n Rule 604.
In the absence of withdrawal by the Convening Authority, the next logical step is for one of the parties to file a motion with the Commission (Judge Col. James Pohl) to dismiss the conspiracy charges on jurisdictional grounds, which are non-waivable. Rule 907(b)(1)(A). This could be done by either the defense or, theoretically, the prosecution. (Dismissal for lack of jurisdiction does not require that the motion be brought by the defense, unlike some of the other grounds for dismissal. Rule 907(b)(2)–(3).) If Judge Pohl dismisses the charge, the government could file an interlocutory appeal with the Court of Military Commission Review (and thus to the D.C. Circuit and ultimately to the Supreme Court). Rule 908(a)(1). What's less clear is whether the defense (or indeed prosecution, given Brig. Gen. Martins's previous recommendation) could immediately appeal Judge Pohl's denial of the motion to dismiss. (Lawfare hivemind, feel free to chime in.)
In this case, the defense has moved for dismissal on the conspiracy charges, and the prosecution will apparently acquiesce in that decision. The Office of Chief Defense Counsel has released this statement to that effect:
Convening Authority demonstrates its non‐neutrality
January 18, 2013
Today, the Department of Defense announced that the Convening Authority has refused the Chief Prosecutor’s request to withdraw and dismiss the conspiracy charge against the 9/11 defendants. The Convening Authority, which has no analogue in a civilian court, determines the charges, authorizes the death penalty, decides the funding for the defense, and picks the panel of military officers to decide the case.
James Connell, attorney for accused co‐conspirator Ammar al Baluchi, said, “The Convening Authority's decision to require a charge to go forward when the Chief Prosecutor says that it is not legally viable demonstrates that the Convening Authority is in no way a neutral body. The Convening Authority's attempt to drive the prosecution forward shows that the military commission structure is fundamentally unfair.” The defense has challenged the neutrality of the Convening Authority in a motion (AE091) scheduled to be heard in February.
The prosecution has not asked the military commission to dismiss the conspiracy count, but rather has stated that it will acquiesce in a defense motion to dismiss the charge on certain conditions (AE107A). These motions (AE107 and AE120) are not scheduled for hearing in January or February, which means the military commission will probably address the issue at the hearing April 22‐26.
The filings listed in the final paragraph are not yet publicly available from the Military Commission's website.