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10 U.S. Code § 749 - Command: commissioned officers in same grade or corresponding grades on duty at same place

(a)
When the Army, Navy, Air Force, Marine Corps, Space Force, or Coast Guard, as the case may be, has on duty in the same area, field command, or organization two or more commissioned officers of the same grade who are otherwise eligible to command, the President may assign the command without regard to rank in that grade.
(b)
When officers of the Army, Navy, Air Force, Marine Corps, Space Force, or Coast Guard are on duty in the same area, field, command, or organization and two or more commissioned officers of different services, who are otherwise eligible to command, have the same grade or corresponding grades, the President may assign the command without regard to rank in that grade.
Editorial Notes
Amendments

2021—Pub. L. 116–283 substituted “Marine Corps, Space Force,” for “Marine Corps,” in subsecs. (a) and (b).

Statutory Notes and Related Subsidiaries
Transfer of Functions

For transfer of authorities, functions, personnel, and assets of the Coast Guard, including the authorities and functions of the Secretary of Transportation relating thereto, to the Department of Homeland Security, and for treatment of related references, see sections 468(b), 551(d), 552(d), and 557 of Title 6, Domestic Security, and the Department of Homeland Security Reorganization Plan of November 25, 2002, as modified, set out as a note under section 542 of Title 6.

Executive Documents
Delegation of Authority

For delegation of authority of President under this section, see section 1 of Ex. Ord. No. 12765, June 11, 1991, 56 F.R. 27401, set out as a note under section 113 of this title.