14 U.S.C. § 3737

(a) The Secretary shall assign a running mate to each Reserve officer in an active status not on the active duty promotion list. The officer initially assigned as a running mate under this section shall be that officer on the active duty promotion list of the same grade who is next senior in precedence to the Reserve officer concerned. An officer who has twice failed of selection or who has been considered but has not been recommended for continuation under section 2150 of this title shall not be assigned as a running mate under this section. (b) A Reserve officer in an active status not on the active duty promotion list shall be assigned a new running mate as follows: (1) If a previously assigned running mate is promoted from below the promotion zone, is removed from the active duty promotion list, suffers a loss of numbers, fails of selection, fails to qualify for promotion, or declines an appointment after being selected for promotion, the new running mate shall be that officer on the active duty promotion list, of the same grade, who is next senior to the previous running mate and who is, or may become, eligible for consideration for promotion. If the previous running mate was on a list of selectees for promotion, the new running mate shall be that officer on the active duty promotion list, of the same grade, who is on a list of selectees for promotion and who is next senior to the previous running mate. (2) If a Reserve officer suffers a loss of numbers, the new running mate shall be that officer on the active duty promotion list who, after the loss of numbers has been effected, is the running mate of the Reserve officer next senior to the Reserve officer concerned. (3) If a Reserve officer is considered for promotion and fails of selection, fails to qualify for promotion, declines an appointment after being selected for promotion, or has his or her name removed from a list of selectees for promotion, and that officer’s running mate is promoted, the new running mate shall be that officer on the active duty promotion list, of the same grade, who, at the time the previous running mate was considered for promotion, was next senior to the previous running mate, was eligible for consideration for promotion, and whose name was not included on a list of selectees for promotion. (4) In a situation not expressly covered by this subsection, the Secretary may assign a new running mate as necessary to effect the intent of this section that inequitable changes of precedence do not occur. (c) A Reserve officer on the active duty promotion list shall, to the extent practicable and consistent with the limitations imposed by this section, be assigned as the running mate of all Reserve officers junior to the officer, who are in an active status not on the active duty promotion list, and who had a running mate in common with the officer just prior to the time the officer was placed on the active duty promotion list. (d) The Secretary may adjust, as necessary, the date of rank of a Reserve officer not on active duty so that the date will correspond with that of the running mate assigned to the officer in accordance with this section. If an overpayment of pay or allowances results from adjusting the date of rank, the overpayment is not subject to recoupment.