Parts of the Act you should know: Challenge judge? Judge decides challenge

[ryanus]

(a) CHALLENGES AUTHORIZED.—The military
judge and members of a military commission under this
chapter may be challenged by the accused or trial counsel
for cause stated to the commission. The military judge
shall determine the relevance and validity of challenges for
cause. The military judge may not receive a challenge to
more than one person at a time. Challenges by trial counsel
shall ordinarily be presented and decided before those
by the accused are offered.

http://frwebgate.access.gpo.gov/cgi-bin/getdoc.cgi?dbname=109_cong_bills&docid=f:h6166eh.txt.pdf

So...the accuse challenges the judges, and then the judges decides whether the challenge is valid. Nice play.