Negating mens rea Flashcards
Mistake of law
Generally, ignorance of the law is no excuse—i.e., mistakes about what the law forbids and permits usually do not negate mens rea.
Reliance on a lawyer’s advice generally does not excuse mistake of law, and it usually does not fall into the reliance on government interpretations exception.
Mistake of fact: strict liability
Mistake of fact is never a defense to strict liability crimes, e.g., a liquor store’s reasonable mistake that the fake ID was real, liquor laws being strict liability crimes.
Involuntary intoxication
Involuntary intoxication occurs when a person:
(1) Doesn’t realize that she has received an intoxicating substance, e.g., “date rape” drugs;
(2) Is coerced into ingesting a substance; or
(3) Has an unexpected or unanticipated reaction to prescription medication.
Involuntary intoxication can be a valid defense to specific-intent, general-intent, and malice crimes should the intoxication negate the mens rea necessary for the crime.
MIstake of law: exceptions
Some mistakes of law may negate mens rea:
(1) Reliance on high-level government interpretations, e.g., regulations interpreting statutes;
(2) Lack of notice;
(3) MIstakes of law that go to an element of specific intent.
Mistake of fact: general intent crimes
Mistake of fact is a defense only if the mistake is reasonable and goes to criminal intent.
Mistake of fact: specific intent crimes
Mistake of fact is a defense even if the mistake was unreasonable, as the only question is whether the defendant held the mistaken belief.
Insanity: burden of proof
In the majority of jurisdictions, the defendant has the burden of proving insanity either by a preponderance of the evidence or clear and convincing evidence.
A minority of jurisdictions require the defendant to introduce evidence of insanity, and then the burden of persuasion shifts to the prosecution to prove sanity beyond a reasonable doubt.
Voluntary intoxication: common law
At common law, voluntary intoxication is a defense only to specific-intent crimes—and only if it prevented the defendant from forming the mens rea.
It is not a defense to general intent crimes or crimes involving malice, recklessness, negligence, or for strict-liability crimes.
It does not provide a defense if the defendant got intoxicated in order to commit the crime.
Insanity: M’Naughten
Under the M’Naughten test, the defendant must not have known:
(1) the nature of the act because of a mental disease or defect; or
(2) that the act was wrong because of a mental disease or defect.
Insanity: irresistible impulse
Under the irresistible impulse approach to insanity, the defendant’s mental disease or defect must prevent her from controlling herself.
Insanity: Durham rule
Under the Durham rule, the defendant is legally insane if the defendant would not have committed the crime but for her having a mental disease or defect.
The Durham rule is very defendant friendly—and consequently, very rarely used.
Insanity: Model Penal Code
Under the Model Penal Code, a defendant is legally insane if, because of a mental disease or defect, the defendant did not have substantial capacity:
(1) to appreciate the wrongfulness of his actions or
(2) to conform his conduct to the law.
Voluntary intoxication: Model Penal Code
Under the Model Penal Code, voluntary intoxication is only a defense to crimes where:
(1) a material element requires purpose or knowledge; and
(2) the intoxication prevents formation of that mental state.
