In law, competence concerns the mental capacity of an individual to participate in legal proceedings. Defendants that do not possess sufficient "competence" are usually excluded from criminal prosecution, while witnesses found not to possess requisite competence cannot testify.

In the United States

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In United States law, this protection has been ruled by the United States Supreme Court to be guaranteed under the due process clause. If the court determines that a defendant's mental condition makes him unable to understand the proceedings, or that he is unable to help in his defense, he is likely to be found incompetent. The specific test, as determined in Dusky v. United States, is whether the accused "has sufficient present ability to consult with his lawyer with a reasonable degree of rational understanding—and whether he has a rational as well as factual understanding of the proceedings against him." Being determined incompetent is substantially different from undertaking an insanity defense; competence regards the defendant's state of mind at the time of the trial, while insanity regards his state of mind at the time of the crime.

See also

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• principle of conferral in the context of European Union law

Evidence