A mistake in point of law is, in criminal cases, no sort of defense.

Explanation

(English-origin maxim.) In criminal prosecutions, a defendant cannot escape liability by claiming he did not know his act was illegal — the law presumes knowledge of its own commands, and mistake of law is no defense to a criminal charge.

Where this applies

• A driver is charged with operating a vehicle with an expired registration; he argues he thought the registration was still valid, but the court convicts him because mistake of law is no defense in a criminal case.
• A business owner is prosecuted for violating environmental regulations he genuinely believed did not apply to his industry; the court holds that his legal error cannot shield him from criminal liability.
• A hunter is charged with poaching in a protected area; he claims he misread the boundary map's legal description, but the court rules that misunderstanding the law is never a criminal defense.