(a) Summary courts-martial may be convened by:

(1) Any person who may convene a general or special court-martial;

(2) The commanding officer of a detached or separate company or corresponding unit or other detachment of a force of the organized militia; or

(3) The commanding officer or officer in charge of any other command when empowered by the adjutant general.

(b) When only one officer is present with a command or detachment, he shall be the summary court-martial of that command or detachment and shall hear and determine all summary court-martial cases brought before him. However, summary courts-martial may be convened in any case by superior competent authority when deemed desirable by him.