1. (a) 28 Years of Active Commissioned Service.— Except as provided in subsection (b) and as provided under section 637(b) of this title, each officer of the Regular Army, Regular Air Force, or Regular Marine Corps who holds the regular grade of lieutenant colonel, and each officer of the Regular Navy who holds the regular grade of commander, who is not on a list of officers recommended for promotion to the regular grade of colonel or captain, respectively, shall, if not earlier retired, be retired on the first day of the month after the month in which he completes 28 years of active commissioned service.

2. (b) Exceptions.— Subsection (a) does not apply to the following:

   1. (1) An officer of the Navy or Marine Corps who is an officer designated for limited duty to whom section 5596(e) or 6383 of this title applies.
   2. (2) An officer of the Navy or Marine Corps who is a permanent professor at the United States Naval Academy.

(Added Pub. L. 96–513, title I, § 105, Dec. 12, 1980, 94 Stat. 2862; amended Pub. L. 98–525, title V, § 529(b), title XIV, § 1405(12), Oct. 19, 1984, 98 Stat. 2526, 2622; Pub. L. 102–484, div. A, title V, § 504(a), Oct. 23, 1992, 106 Stat. 2403; Pub. L. 103–160, div. A, title V, § 561(e), Nov. 30, 1993, 107 Stat. 1667; Pub. L. 105–261, div. A, title V, § 504(a), Oct. 17, 1998, 112 Stat. 2004; Pub. L. 109–163, div. A, title V, § 509(a)(1), Jan. 6, 2006, 119 Stat. 3229.)

Amendments 2006—Pub. L. 109–163 designated existing provisions as subsec. (a), inserted heading, substituted “Except as provided in subsection (b) and as provided” for “Except an officer of the Navy or Marine Corps who is an officer designated for limited duty to whom section 5596(e) or 6383 of this title applies and except as provided”, and added subsec. (b).

1998—Pub. L. 105–261 substituted “Except an officer of the Navy or Marine Corps who is an officer designated for limited duty to whom section 5596(e) or 6383 of this title applies” for “Except an officer of the Navy designated for limited duty to whom section 5596(e) of this title applies and an officer of the Marine Corps designated for limited duty to whom section 5596(e) or section 6383 of this title applies” and struck out at end “During the period beginning on July 1, 1993, and ending on October 1, 1999, the preceding sentence shall not apply to an officer of the Navy designated for limited duty to whom section 6383 of this title applies.”

1993—Pub. L. 103–160 substituted “October 1, 1999” for “October 1, 1995”.

1992—Pub. L. 102–484 inserted at end “During the period beginning on July 1, 1993, and ending on October 1, 1995, the preceding sentence shall not apply to an officer of the Navy designated for limited duty to whom section 6383 of this title applies.”

1984—Pub. L. 98–525, § 1405(12), substituted “28” for “twenty-eight”.

Pub. L. 98–525, § 529(b), substituted “Except an officer of the Navy designated for limited duty to whom section 5596(e) of this title applies and an officer of the Marine Corps designated for limited duty to whom section 5596(e) or section 6383 of this title applies” for “Except an officer of the Navy and Marine Corps who is an officer designated for limited duty (to whom section 5596(e) or 6383 of this title applies)”.