Us Code § 949k - Defense of lack of mental responsibility

Full text of Us Code United States Code § 949k — Defense of lack of mental responsibility, with citation guidance and answers to common questions.

§ 949k. Defense of lack of mental responsibility

(a) Affirmative Defense.—It is an affirmative defense in a trial by military commission under this chapter that, at the time of the commission of the acts constituting the offense, the accused, as a result of a severe mental disease or defect, was unable to appreciate the nature and quality or the wrongfulness of the acts. Mental disease or defect does not otherwise constitute a defense.

(b) Burden of Proof.—The accused in a military commission under this chapter has the burden of proving the defense of lack of mental responsibility by clear and convincing evidence.

(c) Findings Following Assertion of Defense.—Whenever lack of mental responsibility of the accused with respect to an offense is properly at issue in a military commission under this chapter, the military judge shall instruct the members as to the defense of lack of mental responsibility under this section and shall charge the members to find the accused—

(1) guilty;

(2) not guilty; or

(3) subject to subsection (d), not guilty by reason of lack of mental responsibility.


(d) Majority Vote Required for Finding.—The accused shall be found not guilty by reason of lack of mental responsibility under subsection (c)(3) only if a majority of the members present at the time the vote is taken determines that the defense of lack of mental responsibility has been established.

(Added Pub. L. 111–84, div. A, title XVIII, §1802, Oct. 28, 2009, 123 Stat. 2588.)


Editorial Notes

Prior Provisions

A prior section 949k, added Pub. L. 109–366, §3(a)(1), Oct. 17, 2006, 120 Stat. 2615, related to the defense of lack of mental responsibility, prior to the general amendment of this chapter by Pub. L. 111–84.

About This Section

10 U.S.C. § 949k is part of Title 10 of the United States Code. The United States Code is the official codification of federal statutes maintained by the Office of the Law Revision Counsel of the U.S. House of Representatives. Congress amends the Code through new public laws, which are eventually incorporated into the relevant title.

This section may be cited in legal writing as 10 U.S.C. § 949k. For the most current official text, including any recent amendments, use the official source links below. Do not rely on this page as the sole authority for legal citation or litigation.

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Sources

Source: official Us Code text · Last verified 2026-08-27

Frequently Asked Questions About Us Code § 949k

What does United States Code § 949k cover?

Section 949k ("Defense of lack of mental responsibility") is part of the United States Code, the codified statutory law of Us Code. It sets out the legal rule or procedure described in the text above. Statutes are amended regularly, so always verify against the official source.

How do I cite Us Code § 949k?

A common citation format is "United States Code § 949k" (Us Code). Legal writing may require the code abbreviation, section number, and year or edition. Match the style required by your court, professor, or publisher.

Is this the official text of Us Code law?

No. This page is for research and education and may not include the most recent amendments. For official current law, check the Us Code official source linked on this page or consult a licensed Us Code attorney.

How does Us Code § 949k apply to my situation?

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Sources & Verification

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