i.e., he's fucked.
"No person shall be held to answer for a capital, or otherwise infamous crime, unless on a presentment or indictment of a Grand Jury, except in cases arising in the land or naval forces, or in the Militia, when in actual service in time of War or public danger...."
"In all criminal prosecutions, the accused shall enjoy the right to a speedy and public trial, by an impartial jury of the State and district where in the crime shall have been committed, which district shall have been previously ascertained by law, and to be informed of the nature and cause of the accusation; to be confronted with the witnesses against him; to have compulsory process for obtaining witnesses in his favor, and to have the Assistance of Counsel for his defense."
Civilian juries are based on English civilian common law juries. I would strongly suspect military court-martial juries have the same basis, although Wikipedia notes "Members of a court-martial are commissioned officers, unless the accused is a warrant officer or enlisted member and requests that the membership reflect their position by including warrant or enlisted members."