46 (2) I n this article, the word "unit" means any regularly organized body as defined by the Secretary concerned, but in no case may it be a body larger than a company, squadron, ship's crew, or body corresponding to one of them. (d)(1) Vhen it can be avoided, no member of an armed force niay be tried by a court-martial any member of which is junior to him in rank or grade. (2) Vhen convening a court-martial, the convening authority shall detail as members thereof such members of the armed 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 an armed force is eligible to serve as a member of a general or special court-martial when he is the accuser or a witness for the prosecution or has acted as investigating officer or as counsel in the same case. § 826. Art. 26. Law officer of a general court-martial (a) The authority convening a general court-martial shall detail as law officer thereof a commissioned officer who is a member of the bar of a Federal court or of the highest court of a State and who is certified to be qualified for such duty by the Judge Advocate General of the armed force of which he is a member. No person is eligible to act as law officer in a case if he is the accuser or a witness for the prosecution or has acted as investigating officer or as counsel in the same case. (b) The law officer may not consult with the members of the court, other than on the form of the findings as provided in section 839 of this title (article 39), except in the presence of the accused, trial counsel, and defense counsel, nor may he vote with the members of the court. § 827. Art. 27. Detail of trial counsel and defense counsel (a) For each general and special court-martial the authority convening the court shall detail trial counsel and defense counsel, and siich assistants as lie considers appropriate. No person who has acted as investigating officer, law officer, or court member in any case may act later as trial counsel, assistant trial counsel, or, unless expressly requested by the accused, as defense counsel or assistant defense counsel in the same case. No person who has acted for the prosecution may act later in the same case for the defense, nor may any person who has acted for the defense act later in the same case for the prosecution. (b) Trial counsel or defense counsel detailed for a general courtmartial— (1) must be a judge advocate of the Army or the Air Force, or a law specialist of the Navy or Coast Guard, who is a graduate of an accredited law school or is a member of the bar of a Federal court or of the highest court of a State; or must be a member of the bar of a Federal court or of the highest court of a State; and (2) must be certified as competent to perform such duties by the Judge Advocate General of the armed force of which he is a member.