(a) Commissioned officer.--Any commissioned officer of the State military forces who is not a member of the same unit as the accused is eligible to serve on all courts-martial for the trial of any person who may lawfully be brought before such courts for trial.

(b) Warrant officer.--Any warrant officer of the State military forces who is not a member of the same unit as the accused is eligible to serve on general and special courts-martial for the trial of any person, other than a commissioned officer, who may lawfully be brought before such courts for trial.

(c) Enlisted member.--Any enlisted member of the State military forces who is not a member of the same unit as the accused is eligible to serve on general and special courts-martial for the trial of any enlisted member who may lawfully be brought before such courts for trial. The member shall serve as a member of a court only if, prior to the conclusion of a session called by the military judge under section 5704 (relating to sessions), or prior to trial, or, in the absence of such a session, before the court is assembled for the trial of the accused, the accused has requested orally on the record or in writing that enlisted members serve on it. After such a request, the accused may not be tried by a general or special court-martial, the membership of which does not include enlisted members in a number comprising at least one-third of the total membership of the court, unless eligible members cannot be obtained on account of physical conditions or military exigencies. If such members cannot be obtained, the court may be assembled and the trial held without them, but the convening authority shall make a detailed written statement, to be appended to the record, stating why they could not be obtained.

(d) Ineligible persons.--

(1) Except in exigent circumstances, no person subject to this part may be tried by a court-martial any member of which is junior to him in rank or grade.

(2) When convening a court-martial, the convening authority shall detail as members thereof such members of the State military forces as, in his opinion, are best qualified for the duty by reason of age, education, training, experience, length of service and judicial temperament. No member of the State military forces is eligible to serve as a member of a general or special court-martial when that member is the accuser or a witness or has acted as investigating officer or as counsel in the same case.

(e) Excuse.--Before a court-martial is assembled for the trial of a case, the convening authority may excuse a member of the court from participating in the case. The convening authority may delegate the authority under this subsection to a judge advocate or to any other principal assistant.

(f) Definition.--As used in this section, the following words and phrases shall have the meanings given to them in this subsection unless the context clearly indicates otherwise:

"Unit." Any regularly organized body of the State military forces not larger than a company or a squadron or a body corresponding to one of them.