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Criminal Law
University of Kentucky School of Law
Lawson, Robert G.

Criminal Law Outline

§ Actus Reus + Mens Rea = Crime
§ Culpable Act + Culpable State of Mind = Crime

Actus Reus=culpable act
§ Model Penal Code Act Requirement
o “A person is not guilty of an offense unless his liability is based on conduct which includes a voluntary act or the omission to perform an act of which he is physically capable.”
§ The act separates the mental state from those that actually commit the crime. There is a big jump from thinking about committing a crime to actually committing a crime.
§ Voluntary Act Requirement
o Act alone is not enough; the act must be voluntary
o Voluntary of conscious and volitional movement
o MPC Involuntary Acts
§ Reflex/convulsion
§ Bodily movement during sleep/unconsciousness
§ Hypnosis (most jurisdictions do not recognize)
§ Bodily movement not otherwise product of effort or determination by actor either conscious or habitual
§ Omissions to Act
o Before there can be a crime with a failure to act as the act, there must be a legal duty to act, not just a moral obligation.
o When there is a legal duty to act:
§ Statutory duty (where a failure to act violates a statute)
· Examples: pay taxes, parents provide food and shelter, etc.
§ Status relationship
· Examples: parent/child, spouse, employer/employee
§ Contractual obligation
· Examples: babysitter, someone hired to care for elderly
§ Omissions following an act
· Creation of risk
o Example: Someone that accidentally starts a house fire as a legal duty to stop it.
· Voluntary assistance
o Example: Someone that excludes V from further aid is responsible for V.

Mens Rea= “guilty state of mind”
§ Most crimes have a mental state requirement
§ MPC Mental States
o Purposely (Intentionally)
§ Conduct or result: “Conscious objective
§ Attendant Circumstance: “Aware of existence”
o Knowingly
§ Conduct or Attendant Circumstance: “Aware”
§ Result: “Aware—practically certain”
o Recklessly (any material element)
§ Substantial and unjustifiable risk
§ Gross deviation from ordinary care
§ Awareness of risk and conscious disregard
o Negligently (any material element)
§ Substantial and unjustifiable risk
§ Gross deviation from ordinary care
§ General mens rea
o General mens rea is

traffic offenses
o Statutory evaluation—Absence of mens rea does not always mean SL. Look at history and whether it would place undue burden on the prosecution
§ Extensions of Strict Liability
o Vicarious liability—Employer liability for employee actions
o Accomplice Liability—discussed in detail below

Mistake/Ignorance of Law
§ Generally, mistake of law is not an excuse/defense to a crime.
§ Justification: If ignorance of the law were an excuse, everyone would be making up their own body of criminal law.
§ Exceptions:
o D is relying on an official interpretation of the law (court case, attorney general opinion, etc.)
§ Personal misreading of a statute is not an excuse
§ Reliance on advice from personal counsel is not an excuse
o Ignorance/mistake negates mens rea
§ Very rare that knowledge that the prohibited conduct constitutes an offense is itself an express element of the crime