What does the "insanity defense" argue in criminal law?

The insanity defense in criminal law focuses on the mental state of the defendant at the time the offense was committed. Specifically, it argues that the defendant was legally insane when they engaged in the conduct that constitutes the crime. This means that due to a severe mental disorder or impairment, the defendant either did not understand the nature of their actions or could not distinguish right from wrong.

Legal insanity is distinct from a lack of guilt for the act itself; rather, it acknowledges that mental health issues can impact a person's ability to conform their behavior to the law. The defense typically requires the presentation of medical evidence, often from mental health professionals, to substantiate claims about the defendant's mental condition.

In contrast, the other choices address different legal arguments: contesting the act itself, arguing justification like self-defense, or claiming the actions were justified under certain circumstances. However, none of these relate specifically to the mental state required for an insanity defense.