Under the Model Penal Code (MPC) approach to unreasonable mistakes in self-defense, such mistakes may mitigate the crime.

• A. True
• B. False
• C. It is a complete defense
• D. It increases liability

Answer: (B)

Under the Model Penal Code, self-defense is justified only if the defendant reasonably believes that force is immediately necessary to protect against unlawful harm. The key is reasonableness—the belief must be enough to satisfy a reasonable person under the circumstances. If the belief is plainly unreasonable, the self-defense justification does not apply, so the defendant’s liability for the charged offense remains unchanged. The MPC does not recognize imperfect self-defense as a way to mitigate liability. That’s why an unreasonable mistake in thinking self-defense was necessary does not reduce the crime—it doesn’t provide a defense under the MPC. (Note: this contrasts with common law, where an honest but unreasonable belief could reduce murder to manslaughter.)