California
How Durham v. United States applies in California: state-specific rules, key cases, and bar exam notes for Criminal Law.
In California, the principles from Durham v. United States have influenced the understanding of the insanity defense. California uses the M'Naghten rule, focusing primarily on whether the defendant understood the nature of their act or could distinguish right from wrong at the time of the offense.
Under California Penal Code § 25, a defendant is not criminally responsible if they were mentally incapable of understanding the nature of the act or distinguishing right from wrong due to a mental disorder.
The court upheld the M'Naghten rule, affirming that a defendant must be found mentally incompetent if they cannot understand their actions at the time of the crime.
This case established a broader interpretation of mental illness, allowing for evidence of mental conditions that could impact a defendant's understanding.
The court ruled that a defendant's mental illness must be clearly established to support an insanity defense, reinforcing the M'Naghten standard.
California's approach to the insanity defense under the M'Naghten rule is similar to the federal standard used in most jurisdictions. However, California mandates a stricter evidentiary burden on defendants to establish their mental incapacity during the commission of the crime.
The principles surrounding the insanity defense, particularly related to California Penal Code § 25, are often tested on the California bar exam, especially regarding interpretations of mental competency.