((a)) ** .—** The length of a joint duty assignment shall be not less than two years.

((b)) ** .—** The Secretary of Defense may waive subsection (a) in the case of any officer.

((c)) ** .—** The Secretary of Defense may exclude the following service from the requirement in subsection (a):

((1)) Service in a joint duty assignment in which the full tour of duty in the assignment is not completed by the officer because of—

((A)) retirement;

((B)) release from active duty;

((C)) suspension from duty under section 155(f)(2) or 164(g) of this title; or

((D)) a qualifying reassignment from a joint duty assignment as prescribed by the Secretary of Defense in regulations.

((2)) Service in a joint duty assignment in a case in which the officer’s tour of duty in that assignment brings the officer’s accrued service for purposes of subsection (d)(2) to the requirement in subsection (a).

((d)) ** .—** An officer shall be considered to have completed a full tour of duty in a joint duty assignment upon completion of any of the following:

((1)) A joint duty assignment that meets the requirement in subsection (a).

((2)) Accrued joint experience in joint duty assignments as described in subsection (e).

((3)) A joint duty assignment with respect to which the Secretary of Defense has granted a waiver under subsection (b), but only in a case in which the Secretary determines that the service completed by that officer in that duty assignment shall be considered to be a full tour of duty in a joint duty assignment.

((4)) A second and subsequent joint duty assignment that is less than the period required under subsection (a).

((e)) ** .—** For the purposes of subsection (d)(2), the Secretary of Defense may prescribe, by regulation, certain joint experience, such as temporary duty in joint assignments, joint individual training, and participation in joint exercises, that may be aggregated to equal a full tour of duty. The Secretary shall prescribe the regulations with the advice of the Chairman of the Joint Chiefs of Staff.

((f)) ** .—** The Secretary of Defense may award constructive credit in the case of an officer (other than a general or flag officer) who, for reasons of military necessity, is reassigned from a joint duty assignment within 60 days of meeting the tour length criteria prescribed in subsection (d)(1). The amount of constructive service that may be credited to such officer shall be the amount sufficient for the completion of the applicable tour of duty requirement, but in no case more than 60 days.