How is the "insanity defense" defined in criminal law?

The insanity defense in criminal law is specifically defined as a claim that a defendant was not mentally competent at the time they committed a crime. This defense is based on the principle that individuals should not be held criminally responsible for their actions if they are unable to understand the nature of those actions or differentiate between right and wrong due to mental illness or incapacity.

The legal standard varies by jurisdiction but often involves the evaluation of the defendant's mental state and the use of expert testimony to establish that the defendant could not comprehend their actions or the consequences thereof. This is in stark contrast to simply asserting that a defendant did not participate in the crime, which does not address mental competency. The other options, relating to proving previous innocence or delaying trial proceedings, do not accurately represent the fundamental premise of the insanity defense. Therefore, affirming mental incompetence during the crime is the core of the insanity defense principle in criminal law.