Actus reus Study Guide

📖 Core Concepts Actus Reus – the “guilty act” element; must be a physical act (or legally recognized omission) for criminal liability. Mens Rea – the “guilty mind” element; paired with actus reus to form the basic crime requirement. External/Objective Element – U.S. term for actus reus, emphasizing the outward conduct rather than the mental state. Voluntariness – conduct must be performed voluntarily; involuntary movements (e.g., reflexes, sleep) usually fail to satisfy actus reus. Omission as Actus Reus – a failure to act can count when the law creates a specific duty to act. Possession – treated as a voluntary act in many U.S. jurisdictions, thus meeting the act requirement even though it is not a “movement.” 📌 Must Remember Act Requirement – There must be a bodily movement (voluntary) or a legally‑required omission. Status ≠ Act – Mere status (e.g., being a drug addict) does not satisfy actus reus (Robinson v. California). Result Crimes – The act must cause a prohibited result (e.g., homicide requires causing death). Legal Duty Triggers Omission Liability – Statute expressly criminalizes the omission or a duty arises from contract, assumed care, creation of danger, or official position. No Good‑Samaritan Rule (Eng. law) – Moral duty to help does not create criminal liability. MPC Involuntary Conduct Categories Reflex or convulsion Movement during unconsciousness/sleep (automatism) Conduct under hypnosis Movement not produced by the actor’s effort (conscious or habitual) 🔄 Key Processes Determine if Conduct Exists Identify a bodily movement → proceed. If only a status, stop (no actus reus). Assess Voluntariness Check for reflex, sleep, hypnosis, or other involuntary categories → likely not actus reus. If voluntary, continue. Check for Omission Does a statute or duty require action? → If yes, omission satisfies actus reus. Result Requirement (if applicable) Verify that the voluntary act caused the prohibited result. 🔍 Key Comparisons Act vs. Omission – Act: positive bodily movement; Omission: failure to move when a legal duty exists. Voluntary Conduct vs. Involuntary Conduct – Voluntary: intentional or reckless movement; Involuntary: reflex, sleep, hypnosis, or non‑effort movements (no liability). U.S. vs. English Law on Omission – U.S. (MPC) allows statutory omission; English law limits liability to specific duty‑of‑care categories and lacks a Good Samaritan rule. ⚠️ Common Misunderstandings “Any failure to help is punishable.” – Wrong in English law; only when a legal duty is present. “Being addicted makes you liable for possession offenses.” – Robinson v. California says status alone is not an act. “All unconscious actions are crimes.” – Automatism (sleep, seizure) generally negates voluntariness unless the actor knowingly created the risk. 🧠 Mental Models / Intuition “Movement + Will = Crime” – Picture a scale: a physical movement must be coupled with a voluntary will (or a required duty) to tip toward liability. “Duty = Bridge” – Omission liability only crosses the bridge when a legal duty (contract, assumed care, official role) is the support. 🚩 Exceptions & Edge Cases Epileptic Seizure – Not liable unless the person knowingly engaged in dangerous conduct despite known seizure risk (People v. Decina). Possession – Criminalized even though it lacks a physical movement; treated as voluntary in many U.S. jurisdictions. Statutory Omission – An omission can be punishable solely because a statute declares it so, regardless of any traditional duty. 📍 When to Use Which Use the “Duty Test” when evaluating an omission: look for statutory language or established duty categories (contract, assumed care, creation of danger, official position). Apply the “Voluntariness Filter” when the conduct is questionable (e.g., seizure, sleepwalking); if any MPC involuntary category fits, exclude actus reus. Invoke “Result Requirement” only for crimes labeled as result crimes (e.g., homicide, arson). 👀 Patterns to Recognize Status‑Only Facts → No Actus Reus (e.g., addiction, membership). Presence of a Legal Duty → Omission Liability (look for contracts, official roles, created hazards). Involuntary Descriptors (reflex, sleep, hypnosis) → Likely No Liability. 🗂️ Exam Traps Distractor: “Any failure to aid is criminal.” – Wrong under English law; no Good Samaritan rule. Distractor: “An epileptic seizure automatically creates liability.” – Only if the person knowingly risked danger. Distractor: “Possession is never an actus reus because it’s not movement.” – In many U.S. jurisdictions, possession is treated as a voluntary act. Distractor: “Mere status (e.g., drug addict) satisfies actus reus.” – Refuted by Robinson v. California. --- Review these bullets right before the exam; they capture the high‑yield points you’ll need to spot and apply quickly.