Mistake of Law

Question 1

(subject to limited exceptions): mistake or ignorance of the law is not a defense.

Answer 1

Mistake of Law (Common Law)

Question 2

generally, knowledge of the law is not an element of an offense. Therefore, mistake of law (even reasonable mistake) doesn’t ordinarily relieve defendant of liability.

Answer 2

Mistake of Law (MPC)

Question 3

Much tougher rule than for mistake of fact.
Social necessity. Mistake of law defense would reward ignorance and create disincentive to learn the law. We want to promote knowledge of the law.
Concern about fraud. If mistake of law were recognized, it would invite fraud.

Answer 3

Mistake of Law (MPC)

Question 4

Person not guilty of a crime if, at time of offense, he reasonably relied on official statement of law, later determined to be erroneous, obtained from person or public body with responsibility for interpretation, administration, or enforcement of law defining the offense.

Answer 4

Reasonable-Reliance Doctrine (Mistake of Law No-Defense Exception)

Question 5

Official statement of law found in statute, judicial opinion, administrative ruling, or official interpretation of law given by person responsible for law’s enforcement or interpretation (example United States or state attorney general).

Answer 5

Reasonable-Reliance Doctrine (Mistake of Law No-Defense Exception)

Question 6

Actor not excused if relies on her own erroneous reading of law, even if reasonable
Reliance on erroneous advice by private attorney is not a defense
Must be official with authority to interpret, enforce, or administer the criminal law in question
Interpretation must be official – like “opinion letter” not off-the-cuff

Answer 6

Not Reasonable Reliance

Question 7

Ignorance of the law can be an excuse if criminal statute expressly makes knowledge of the unlawfulness of one’s conduct an element of the offense.

Answer 7

Mistake that Negate Mens Rea (Mistake of Law No-Defense Exception)

Question 8

Everyone presumed to know law but there may be exceptional case in which it is grossly unjust to assume person knew of law
Lambert
Punished an omission (failed to register)
Duty to act imposed on basis of status (presence in city)
Offense was malum prohibitum
Bottom line: Lambert had no reason to be aware her omission was punishable.

Answer 8

Fair Notice & Lambert Principal

Mistake of Law No-Defense Exception