Criminal Law & Procedure · Chapter 1 of 1
General Principles of Criminal Liability
63 min7 sectionsFree chapter
The building blocks of every crime and of every Criminal Law answer: how the subject is tested and which law applies; the sources of criminal law and the constitutional limits of legality, vagueness and ex post facto; the voluntary act, the qualifying omission and possession; the common-law mental states and the four Model Penal Code levels, with mistake of fact and mistake of law; concurrence, transferred intent, and actual and proximate cause; corporate and vicarious liability and merger; and the California framing in Penal Code sections 20, 25, 26, 28, 29 and 29.4, with a preview of imperfect self-defense.
Learning objectives
- 1.Identify the voluntary act, or the omission backed by a legal duty, that satisfies the act requirement of a charged crime, and analyze possession as an act.
- 2.Classify the mental state of any crime under the common-law categories (specific intent, malice, general intent, strict liability) and under the four Model Penal Code levels.
- 3.Apply the mistake-of-fact and mistake-of-law rules, and predict when voluntary intoxication helps, by first classifying the crime’s mental state.
- 4.Apply concurrence and transferred intent, and analyze actual and proximate cause, including which intervening acts break the causal chain.
- 5.Recognize the California statutory framing in Penal Code sections 20, 25, 26, 28, 29 and 29.4, and state when to cite it.
1.1 How Criminal Law and Procedure is tested: sources and constitutional limits
Criminal Law asks whether the state may punish a person for an act. Criminal Procedure asks whether the police and the courts followed the Constitution while investigating and prosecuting that person. The bar exam tests both under one subject name, and one essay can cover both. This chapter teaches the general part of Criminal Law: the four building blocks that every crime shares.
Criminal Law and Procedure is tested on both exam days, in the MBE and in the essays; the table below gives the numbers. Recent essay draws: February 2024 (with Evidence), February 2025, and July 2025 (with Professional Responsibility).
| Item | Detail |
|---|---|
| MBE weight | 25 scored questions out of 175. About half test the constitutional protection of accused persons (Fourth, Fifth and Sixth Amendments). The rest cover homicide, other crimes, inchoate crimes and parties, and general principles. |
| Essay frequency | Criminal Procedure: 22 of the last 50 California exams (44 percent). Criminal Law: 17 of 50 (34 percent). Most-tested rules: Fourth Amendment standing 15, Miranda 12, exclusionary rule 11, murder 8, warrant requirement 8. |
| California law | Low. Answer under general principles unless the call names California. The Content Map lists unconsciousness, unreasonable self-defense and diminished capacity among the defenses; California has its own rules on all three (section 6). |
| NextGen status | Criminal Law and Procedure is a foundational subject on the NextGen bar exam, which California adopts from July 2028. The rules in this book carry over. |
| Exam dates in the current format | February 23 to 24, 2027; July 27 to 28, 2027 (anticipated); February 2028 is the last administration of the current two-day format. |
Note
The default sentence on the essay booklet
The instructions for every essay set the default law. They say: “Unless a question expressly asks you to use California law, you should answer according to legal theories and principles of general application”. For Criminal Law that means the common-law rules as most American courts now apply them, plus the Model Penal Code where it has become the modern rule.
Sources of criminal law
American criminal law began as English common law: judge-made definitions of crimes such as murder, larceny and burglary. Today every state defines its crimes by statute, and many states have abolished common-law crimes. California did so in Cal. Penal Code § 6. The Model Penal Code (MPC), published by the American Law Institute in 1962, is not law anywhere by itself. But more than half the states rebuilt their codes on it, and the MBE treats its mental-state scheme as the modern rule.
Model Penal Code – A model criminal statute published by the American Law Institute in 1962 as a template for state codes. It is not law, but many state codes and the MBE’s mental-state vocabulary follow it.American Law Institute, Model Penal Code (1962)
For the exam, think of three layers. First, the common-law rule, which the MBE still uses to define most crimes. Second, the statute in the question, which controls whenever it is quoted. Third, the MPC, which supplies the four mental states and the modern approach to mistake and causation. When the question is silent, the MBE expects the majority rule.
Why the law punishes
Courts give five reasons for punishment. Retribution punishes because the offender deserves it. General deterrence warns other people not to commit the crime. Specific deterrence warns this offender not to repeat it. Incapacitation keeps a dangerous offender away from the public. Rehabilitation tries to change the offender. Essays use them to argue how severely conduct should be punished.
Constitutional limits on criminal statutes
A legislature can make almost any conduct a crime, but the Constitution sets three limits that appear on the MBE. Each protects the same value: a person must be able to know, before acting, what the law forbids. Courts call this value the principle of legality. They also apply it when they interpret statutes: a criminal statute is read narrowly, and doubts about its meaning go to the defendant. That interpretive rule is the rule of lenity.
principle of legality – No conduct is a crime, and no punishment may be imposed, unless a statute defined the crime and fixed the punishment before the conduct occurred.
rule of lenity – The rule that an ambiguous criminal statute is read narrowly, in the defendant’s favor.
Example
The loitering statute
A California statute made it a crime to loiter on the streets and to fail to provide “credible and reliable” identification when a police officer asked for it. A man was stopped or arrested under the statute about 15 times in 2 years while walking in various neighborhoods.
Analysis
In Kolender v. Lawson the Supreme Court held the statute void for vagueness. The words “credible and reliable” gave no standard that an ordinary person could follow. Worse, they left the police free to decide who had complied. The statute failed both tests: notice, and limits on arbitrary enforcement.
Outcome
The statute was unconstitutional on its face; no one could be convicted under it.
ex post facto law – Latin for “after the fact”: a penal law that reaches back to conduct done before the law was passed and makes the defendant’s position worse.
The four kinds of forbidden law come from Calder v. Bull. A new law that helps the defendant, such as a lighter sentence, is not ex post facto. In Stogner v. California the Court applied the clause to a law that revived a prosecution after its time limit had already run.
Key point
Legality is a timing rule. A legislature may not punish past conduct or increase its punishment. A court may not apply an unforeseeable new reading of a crime to conduct that came before it.
The attack order
Every Criminal Law and Procedure answer follows the same six-step route, shown below. Chapter 14 teaches the full method with two past essays.
Elements
The Criminal Law and Procedure attack order
Every Criminal Law and Procedure answer, essay or MBE, follows these six steps.
- 1.1: Applicable law: general principles; apply any statute the question quotes.
- 2.2: Crimes: for each crime, the act, the mental state, concurrence, causation and any result (this chapter).
- 3.3: Parties: accomplices and co-conspirators (chapter 2).
- 4.4: Inchoate offenses: solicitation, conspiracy, attempt; then merger (chapter 2).
- 5.5: Defenses: justification, excuse, mistake, intoxication, insanity (chapter 6).
- 6.6: Criminal Procedure: Fourth, Fifth and Sixth Amendment issues, then the exclusionary rule (chapters 7 to 13).
Any one suffices.
Exam tip
Open every crime with its building blocks in one sentence each: act, mental state, causation, result. Graders reward headings and explicit rule statements, so state each element before the conclusion. Criminal Law: 17 of the last 50 essay exams.
Key notes
- 1.Crim is on both days: 25 scored MBE questions, half on constitutional protections; essays on 22 (procedure) and 17 (law) of 50.
- 2.Default law is general principles: the common law as modified by statute and the MPC; a quoted statute always controls.
- 3.Three constitutional limits: void for vagueness, no ex post facto laws, no unforeseeable retroactive expansion of a crime by a court.
- 4.Attack order: applicable law, crimes (act, mental state, causation), parties, inchoate offenses, defenses, then procedure.
1.2 Actus reus: the voluntary act, omission and possession
Every crime begins with conduct. The law punishes what a person does, not what a person is or thinks. Lawyers call this requirement the actus reus (Latin: the guilty act). It takes three forms on the exam: a voluntary act, a failure to act where the law imposes a duty, and possession. MBE questions hide the act issue inside a sympathetic fact pattern: a seizure, a sleepwalker, a bystander who watches a stranger drown. Find the act before you discuss the mental state.
actus reus – The physical part of a crime: a voluntary act, or an omission where the law imposes a duty to act, that causes any result the crime requires.
Elements
Not a voluntary act
The MPC lists four kinds of movement that are not voluntary acts (§ 2.01(2)).
- 1.Reflex or convulsion: An epileptic seizure, a sneeze, a knee-jerk reaction.
- 2.Unconsciousness or sleep: Sleepwalking, a loss of consciousness from a head injury or a diabetic episode, movement during a coma.
- 3.Hypnosis: Conduct during hypnosis or resulting from a hypnotic suggestion.
- 4.Not the actor’s effort: A movement that is not the product of the actor’s effort or determination, such as a person pushed into another.
Any one suffices.
The act need not be the last movement before the harm. Courts look at the whole course of conduct. Suppose a driver knows that he has seizures but drives anyway, and crashes during a seizure. Starting the car was his voluntary act. A driver who has never had a seizure is different. His first seizure at the wheel is not a voluntary act, and there is no earlier choice to blame.
Case
Robinson v. California, 370 U.S. 660 (1962) (U.S. Supreme Court 1962)
Facts
A California statute made it a crime to “be addicted to the use of narcotics”. Robinson was convicted on evidence of needle marks and his admission of past drug use. There was some evidence that he had used drugs in Los Angeles. But the jury was told it could convict him for addiction alone, even if it disbelieved that evidence.
Holding
A state may not punish a person for the status of being an addict. Addiction is an illness. Punishing a condition, without any act, is cruel and unusual punishment under the Eighth and Fourteenth Amendments.
Why it matters
The constitutional floor under the act requirement: a statute must punish conduct, not a condition. Powell v. Texas later upheld a conviction for being drunk in public, because appearing in public while drunk is an act.
Omission: a failure to act
The general rule is that there is no duty to act. A stranger who watches a child drown commits no crime, however simple the rescue would have been. But an omission counts as an act when three things are true. The law imposed a duty to act; the person knew the facts that created the duty; and the person could have performed the act. The MBE asks one question above all: where did the duty come from?
Elements
Five sources of a legal duty to act
Find one of these before you hold anyone liable for doing nothing.
- 1.Statute: A law requires the act: filing a tax return, reporting an accident, a parent’s duty to support a child.
- 2.Contract: The defendant was paid to protect or care for the victim: a lifeguard, a nurse, a babysitter.
- 3.Special relationship: Parent and child, spouses, and a person who took a dependent into the home; the duty is to protect and to seek help.
- 4.Voluntary assumption of care: The defendant began to help, then stopped in a way that left the victim worse off or kept others away.
- 5.Creation of the peril: The defendant caused the danger, even innocently, and then failed to give aid or warning.
Any one suffices.
Example
Lifeguard and bystander
A swimmer gets into difficulty at a public beach. A lifeguard on duty sees the swimmer but stays in his chair because the water is cold. A bystander on the sand, an excellent swimmer, also sees the swimmer and does nothing. The swimmer drowns.
Analysis
The lifeguard had a duty by contract. His omission is an act, and he can be liable for a homicide offense if his mental state and causation are proved. The bystander had no duty: no statute, contract, relationship, assumption of care or creation of the peril. The bystander commits no crime, whatever a moral code would say.
Outcome
Same omission, different result. The only difference is the source of the duty.
IRAC
- Issue
- Whether [Defendant]’s failure to [rescue / summon help / act] satisfies the act requirement for [crime].
- Rule
- A crime requires a voluntary act. A failure to act is enough only if the law imposed a duty to act, the defendant knew the facts that created the duty, and the act was possible. A duty arises from a statute, a contract, a special relationship (parent and child, spouses), a voluntary assumption of care, or the defendant’s own creation of the peril.
- Application
- Here, [Defendant] did not [act]. The duty to act came from [statute / contract / special relationship / assumption of care / creation of the peril], because [facts]. [Defendant] knew [the facts that created the duty], and the act was possible because [facts]. [Defendant] will argue that [no duty existed: not the biological parent / only a bystander]. However, [the duty follows the assumed role, not the label].
- Conclusion
- Therefore, [Defendant]’s omission [does / does not] satisfy the act requirement, and the analysis turns to the mental state and causation.
Possession as an act
Two points decide most possession questions. First, the defendant must know that he has the thing and what it is. A person who does not know that a package in his car contains drugs does not possess the drugs. Second, the defendant need not know that the law forbids the thing. A person who knows that the powder is cocaine possesses it, even if he wrongly believes that cocaine is legal. Constructive possession means control, not touch: drugs in the defendant’s locked drawer are in his possession.
Exam tip
When the facts stress that the defendant did not know what was in the bag, the question tests possession, not the mental state of a later crime. Choose the answer that turns on knowing control. The wrong answer will say “strict liability” or “he should have checked”.
Key point
No act, no crime. Look for a willed movement, an omission backed by a legal duty, or knowing possession. Status, thoughts and involuntary movements are never enough.
Key notes
- 1.A crime needs a voluntary act: a willed bodily movement, not a reflex, a seizure, a sleep movement or a pushed body.
- 2.Look at the whole course of conduct; the earlier choice to drive with known seizures is the act.
- 3.A status, such as addiction, cannot be punished (Robinson v. California).
- 4.An omission is criminal only with a legal duty: statute, contract, relationship, assumed care or created peril.
- 5.Possession is knowing control for long enough to end it; it may be constructive or shared.
1.3 Mens rea: common-law categories, MPC levels and mistake
The mens rea (Latin: the guilty mind) is the mental state a crime requires. It decides which defenses work, such as mistake and intoxication. The exam uses two vocabularies at once: the common-law categories that define the crimes, and the four MPC levels that a modern statute uses.
mens rea – The mental state that the definition of a crime requires, with respect to each element, at the time of the act.
The common-law categories
specific intent – An intent to do some further act or to achieve some further result beyond the act itself; for example, larceny requires the intent to deprive the owner permanently.
general intent – The intent only to do the act that the crime forbids, without any further purpose; battery and rape are general-intent crimes.
malice – The mental state for murder and arson: intent to cause the harm, or reckless disregard of an obvious risk of it; no ill will needed.
strict liability – A crime with no mental-state requirement for at least one element; doing the act is enough, so mistake of fact is no defense.
| Category | Meaning | Crimes | Defenses that work |
|---|---|---|---|
| Specific intent | MeaningIntent to bring about a further result or to do a further act | CrimesSolicitation, conspiracy, attempt, first-degree murder, assault (attempted battery), larceny, embezzlement, false pretenses, robbery, burglary, forgery | Defenses that workAny honest mistake of fact, even an unreasonable one; voluntary intoxication |
| Malice | MeaningIntent to cause the harm, or reckless disregard of a high risk of it | CrimesCommon-law murder, arson | Defenses that workOnly a reasonable mistake of fact; no voluntary intoxication |
| General intent | MeaningIntent to do the forbidden act itself | CrimesBattery, rape, kidnapping, false imprisonment | Defenses that workOnly a reasonable mistake of fact; no voluntary intoxication |
| Strict liability | MeaningNo mental state required for the key element | CrimesStatutory rape, selling liquor to a minor, most regulatory and traffic offenses | Defenses that workNo mistake-of-fact or intoxication defense; defenses that deny the voluntary act, and justification or excuse defenses, still apply. |
Mnemonic
FIAT
- F– First-degree murder (premeditated and deliberate)
- I– Inchoate offenses: solicitation, conspiracy, attempt
- A– Assault, in its attempted-battery form
- T– Theft and related crimes: larceny, embezzlement, false pretenses, robbery, burglary, forgery
The specific-intent crimes: for these, an honest mistake of fact and voluntary intoxication can negate the intent.
To classify a crime, read its definition. If it says “with intent to” plus something beyond the act, the crime is specific intent. If it names only the act, the crime is general intent. Murder and arson keep their old word, malice. Strict liability appears only when the legislature clearly intends no mental state, usually for a public-welfare offense.
The four MPC levels
| Level | As to conduct or result | As to a circumstance | Common-law equivalent |
|---|---|---|---|
| Purposely | As to conduct or resultThe conscious object is to engage in the conduct or to cause the result | As to a circumstanceAware of the circumstance, or hopes or believes that it exists | Common-law equivalentSpecific intent |
| Knowingly | As to conduct or resultAware that the conduct is of that nature, or practically certain that the result will follow | As to a circumstanceAware that the circumstance exists; awareness of a high probability is enough (§ 2.02(7), willful blindness) | Common-law equivalentGeneral intent; knowledge |
| Recklessly | As to conduct or resultConsciously disregards a substantial and unjustifiable risk; a gross deviation from the conduct of a law-abiding person | As to a circumstanceConsciously disregards a substantial and unjustifiable risk that the circumstance exists | Common-law equivalentMalice; criminal recklessness |
| Negligently | As to conduct or resultShould be aware of a substantial and unjustifiable risk; a gross deviation from the care of a reasonable person | As to a circumstanceShould be aware of a substantial risk that the circumstance exists | Common-law equivalentCriminal negligence |
material element – An element that concerns the harm or evil the law seeks to prevent, not jurisdiction, venue or time limits; MPC mental states attach to material elements.MPC § 1.13(10)
The MPC levels are ordered: proof of a higher level satisfies a lower one. Non-MPC courts presume the mental state needed to separate wrongful from innocent conduct, and they presume against strict liability. Morissette v. United States read a mental state into a theft statute that stated none. The presumption is weakest for public-welfare offenses. Under the MPC, strict liability is limited mainly to violations, which carry only a fine (MPC § 2.05).
Mistake of fact and mistake of law
Example
The wrong coat
Ben leaves a restaurant and takes a coat from the rack, honestly believing that it is his. It belongs to another customer and is worth more than his own coat. A careful person would have noticed the difference.
Analysis
Larceny requires the intent to steal another person’s property. Ben believed the coat was his, so he had no intent to steal. His mistake negates the specific intent even though it was careless. Contrast battery, a general intent crime: an unreasonable belief that the victim consented is no defense.
Outcome
No larceny.
Case
Lambert v. California, 355 U.S. 225 (1957) (U.S. Supreme Court 1957)
Facts
A Los Angeles ordinance required any person with a felony conviction who stayed in the city for more than 5 days to register with the police. Lambert, a convicted felon, had lived in Los Angeles for years without registering and without knowing of the ordinance.
Holding
Due process forbids punishing a wholly passive failure to register when the person had no actual knowledge of the duty and no reasonable chance to learn of it. Notice is required before such an omission can be punished.
Why it matters
A narrow exception to the ignorance-of-law rule: it needs passive conduct, a registration-type duty and no notice.
Exam tip
Why does the question say the defendant was drunk? Voluntary intoxication helps only against specific-intent crimes; it never excuses battery, rape, arson or a reckless killing. Find the crime on the FIAT list first.
Key notes
- 1.Common-law categories: specific intent (FIAT crimes), malice (murder, arson), general intent, strict liability.
- 2.MPC levels: purposely, knowingly, recklessly, negligently. MPC: silence means recklessness; a stated level covers every material element.
- 3.Courts presume a mental state; strict liability is mainly for public-welfare offenses and MPC violations.
- 4.Mistake of fact must negate the mental state: any mistake for specific intent, a reasonable one for general intent, none for strict liability.
- 5.Mistake of law: no defense except official reliance, a knowledge-of-law element or Lambert notice; intoxication negates only specific intent.
1.4 Concurrence, transferred intent and causation
A crime is not a list of separate elements; the elements must connect. The mental state must exist at the time of the act and prompt it (concurrence). The act must produce the result the crime names (causation). When the harm lands on the wrong person, the law must decide whether the intent follows the bullet (transferred intent).
concurrence – The rule that the mental state must exist at the moment of the act and prompt it. A later intent, or an earlier intent that does not prompt the act, is not enough.
Example
The intent that came later
Cara breaks into a house at night to get out of a storm, intending only to shelter. Once inside, she sees jewelry on a table and takes it.
Analysis
Common-law burglary requires the intent to commit a felony at the time of the breaking and entering. Cara formed the intent to steal after she entered, so the act and the intent do not concur. There is no burglary. She is guilty of larceny for taking the jewelry, and at most of trespass for the entry (she may argue necessity).
Outcome
No burglary; larceny, and at most trespass. Cal. Penal Code § 459 requires the same concurrence: entry “with intent” to steal or commit a felony.
transferred intent – A defendant who intends to harm one person but harms another is guilty of the same crime against the actual victim; the intent transfers.
Example
The missed shot
Dan fires a pistol at Ana, intending to kill her. The bullet misses Ana and kills Ben, a passer-by whom Dan never saw.
Analysis
Dan is guilty of murder of Ben: his intent to kill Ana transfers to Ben. Dan is also guilty of attempted murder of Ana, on his actual intent to kill her. Two crimes, one act. Transferred intent would not make him guilty of attempting to murder a bystander the bullet missed, unless Dan meant to kill everyone in the zone of fire.
Outcome
Murder (Ben) plus attempted murder (Ana).
Causation
Causation matters only for result crimes, above all homicide. The prosecution must prove two links. The first is factual: the act was a but-for cause of the result. The second is legal: the result was close enough to the act, in kind and in manner, to hold the defendant responsible. Most MBE causation questions test the second link with an intervening act: a careless surgeon, a fleeing victim, a second attacker.
actual cause – The but-for cause: the result would not have occurred when it did without the defendant’s act; where two acts each suffice, each is a substantial factor.
proximate cause – The legal cause: the result is a natural and probable consequence of the act, and no unforeseeable intervening act broke the chain.
superseding cause – An unforeseeable intervening act, or an independent deliberate act of a third party, that breaks the causal chain from the defendant’s act.
Elements
Intervening acts: does the chain break?
An intervening act is an event between the defendant’s act and the result.
- 1.Does not break: Ordinary negligence by doctors treating the wound the defendant inflicted, unless it alone caused the death.
- 2.Does not break: The victim’s pre-existing weakness or condition: the defendant takes the victim as he finds her.
- 3.Does not break: A foreseeable response to the danger: a victim who flees into traffic, a rescuer who is hurt.
- 4.Does not break: The victim’s refusal of medical treatment, including refusal on religious grounds (most courts).
- 5.Usually breaks: A free, deliberate act of a third party, done for the third party’s own reasons, that causes the harm.
- 6.Usually breaks: Grossly negligent or intentional mistreatment by a doctor.
- 7.Usually breaks: An unforeseeable natural event or coincidence, such as lightning striking the wounded victim.
Any one suffices.
The test for an intervening act is foreseeability, judged when the defendant acted. A person who stabs another can foresee a hospital, and hospitals make mistakes. Gross negligence or a deliberate wrong by a doctor is not foreseeable in the same way. A second attacker who acts for his own reasons is a superseding cause; a rescuer or a fleeing victim is not.
Hypothetical
The refused transfusion
Dan stabs Ana in the abdomen during an argument outside a bar. Paramedics take her to a hospital, where the doctors tell her that a blood transfusion would almost certainly save her life. Ana refuses the transfusion because of her religious beliefs. The doctors respect her decision, and she dies of blood loss 6 hours later. The medical examiner testifies that the wound was survivable with a transfusion and fatal without one. Dan is charged with murder. He argues that Ana caused her own death by refusing treatment.
Is Dan the actual and proximate cause of Ana’s death?
Analysis
The issue is whether Ana’s refusal of treatment breaks the causal chain. A defendant’s act must be both the actual cause and the proximate cause of the death. An intervening act breaks the chain only if it is unforeseeable, or if it is an independent and deliberate act that makes the original wound a remote cause. A defendant takes the victim as he finds her, including her beliefs. Here, but for the stabbing, Ana would not have died, so actual cause is satisfied. Her refusal did not add a new danger; it only failed to remove the danger that Dan created. Most courts hold that a victim’s refusal of treatment, like a doctor’s ordinary negligence, is within the risk of a serious stab wound and is not a superseding cause. Dan will argue that the refusal was a free and deliberate choice. However, the choice responded to a peril that Dan created, and it did not itself inflict the injury. Therefore, Dan is the proximate cause of Ana’s death, and causation for murder is satisfied.
Exam tip
When a doctor’s error appears in the facts, ask whether it was ordinary or gross. Ordinary negligence does not break the chain unless it alone caused the death; the wrong answer will call the surgeon a superseding cause. Gross negligence or an intentional wrong does.
Key point
Causation has two steps: but for, then foreseeable. A later act breaks the chain only if it was unforeseeable, or was an independent and deliberate act that made the original act remote.
Key notes
- 1.Concurrence: the mental state must exist when the act is done and must prompt it (Pen. Code § 20).
- 2.Transferred intent: intent to harm one person transfers to the person actually harmed, within the same kind of crime.
- 3.Attempt against the intended victim rests on ordinary intent; transferred intent does not create attempts.
- 4.Actual cause: but for the act, or a substantial factor where two causes each suffice.
- 5.Proximate cause: the result must be foreseeable; ordinary medical negligence and the victim’s frailty do not break the chain.
- 6.Superseding causes: unforeseeable events, gross medical mistreatment, and free, deliberate acts of third parties.
1.5 Corporate and vicarious liability; merger
Two short topics complete the general part. The first asks whether a person or an organization can be punished for someone else’s act: vicarious liability for an employee, and criminal liability of a corporation. The second asks how many crimes a single course of conduct produces: the merger rule for inchoate offenses. Both appear on the MBE as one-line distractors, and merger appears in almost every essay that has a conspiracy or an attempt.
vicarious liability – Criminal liability imposed on one person for the act of another, usually on an employer for an employee, without any act or fault of the person held liable.
Keep three ideas apart. Vicarious liability punishes the employer for the employee’s act; it is disfavored, and a statute must impose it clearly. Strict liability removes the mental state but still requires the defendant’s own act. Accomplice liability, taught in chapter 2, requires the defendant’s own act of aid with the intent that the crime be committed. On the MBE, an employer who did not know of, take part in or encourage the crime is liable only if a statute says so.
A corporation acts only through people, so its liability is always derived. Under the federal rule, a corporation is liable for an agent’s crime within the scope of employment, done at least partly to benefit it. The MPC is narrower for most crimes: the board or a high managerial agent must have authorized or recklessly tolerated the offense. Officers remain personally liable for crimes they commit or direct. In United States v. Park a company president was convicted for unsanitary warehouses that he had the power to correct.
Merger
merger – The rule that a defendant cannot be convicted of both a lesser offense and the greater offense it is part of. Solicitation and attempt merge into the completed crime; conspiracy does not.
| Inchoate offense | What happens next | Result |
|---|---|---|
| Solicitation | What happens nextThe person solicited commits the crime | ResultSolicitation merges; the solicitor is liable for the completed crime as an accomplice |
| Solicitation | What happens nextThe person solicited agrees to commit the crime | ResultSolicitation merges into the conspiracy |
| Attempt | What happens nextThe defendant completes the crime | ResultAttempt merges; conviction for the completed crime only |
| Conspiracy | What happens nextA conspirator commits the target crime | ResultNo merger; conviction for both the conspiracy and the completed crime (the MPC merges them unless the goal was broader) |
Example
One robbery, how many crimes?
Ana asks Ben to rob a bank with her. Ben agrees. Two days later they enter the bank, point a gun at the teller and take the money.
Analysis
Ana’s request was a solicitation; it merged into the conspiracy when Ben agreed. The conspiracy does not merge into the robbery. Attempt never arises because the robbery was completed; if it had failed, attempt would stand, and it would merge if the crime were later completed.
Outcome
Each is guilty of conspiracy and robbery: two convictions, not three or four.
Key point
At common law, only conspiracy survives completion. To count the possible convictions, count the completed crimes, add one conspiracy, and drop every solicitation and attempt that reached its goal.
Key notes
- 1.Vicarious liability needs a clear statute; it is limited to regulatory offenses with light penalties.
- 2.A corporation is liable for an agent’s crime within the scope of employment, done partly to benefit it, when the statute reaches corporations.
- 3.MPC: for non-regulatory crimes, the board or a high managerial agent must have authorized or recklessly tolerated the offense.
- 4.Officers stay personally liable for crimes they commit or direct, and under Park for violations they had the power to prevent.
- 5.Solicitation and attempt merge into the completed crime; conspiracy does not at common law, but usually does under the MPC.
1.6 California notes: Penal Code sections 20, 25, 26, 28, 29 and 29.4
Criminal Law essays rarely name California law. When they do, the general rules in this chapter reappear in statutory words. This section shows those Penal Code sections and three points where California has its own rules: unconsciousness, diminished capacity, and imperfect self-defense.
StatuteCA
Cal. Penal Code § 20
Pen. Code § 20 (unity of act and intent)
In every crime or public offense there must exist a union, or joint operation of act and intent, or criminal negligence.Open source
In plain words: section 20 states the act requirement, the mental-state requirement and concurrence in one sentence. “Act” includes an omission where there is a duty. Cal. Penal Code § 15 defines a crime as an act “committed or omitted” in violation of a law. “Intent” is the general word for any mental state, and “criminal negligence” covers the crimes that need only gross negligence, such as involuntary manslaughter.
StatuteCA
Cal. Penal Code § 26
Pen. Code § 26 (persons capable of committing crimes)
All persons are capable of committing crimes except those belonging to the following classes: … Three—Persons who committed the act or made the omission charged under an ignorance or mistake of fact, which disproves any criminal intent. Four—Persons who committed the act charged without being conscious thereof. Five—Persons who committed the act or made the omission charged through misfortune or by accident, when it appears that there was no evil design, intention, or culpable negligence.Open source
In plain words: section 26 lists six classes of people who are not criminally responsible. Two are about the person: children under 14, unless there is clear proof that they knew the act was wrong, and persons who are mentally incapacitated. The other four are mistake of fact that disproves intent, unconsciousness, accident without criminal negligence, and duress by threats to life. Class Four is California’s voluntary-act rule.
StatuteCA
Cal. Penal Code § 29.4
Pen. Code § 29.4 (voluntary intoxication)
Evidence of voluntary intoxication is admissible solely on the issue of whether or not the defendant actually formed a required specific intent, or, when charged with murder, whether the defendant premeditated, deliberated, or harbored express malice aforethought.Open source
In plain words: voluntary intoxication is never a defense in itself (subdivision (a)). Evidence of it is not admissible to show that the defendant lacked implied malice. So a drunk driver who kills cannot use intoxication against a second-degree murder charge based on implied malice.
StatuteCA
Cal. Penal Code § 25(a)
Pen. Code § 25(a) (diminished capacity abolished)
The defense of diminished capacity is hereby abolished. In a criminal action, as well as any juvenile court proceeding, evidence concerning an accused person’s intoxication, trauma, mental illness, disease, or defect shall not be admissible to show or negate capacity to form the particular purpose, intent, motive, malice aforethought, knowledge, or other mental state required for the commission of the crime charged.Open source
Until the early 1980s, a California defendant could argue that a mental abnormality short of insanity reduced murder to manslaughter. The Legislature ended that defense in 1981 by enacting sections 28 and 29. In 1982 the voters added section 25 through Proposition 8.
Today the only question is factual: did this defendant actually form the intent? California courts call this “diminished actuality”. In People v. Saille the Supreme Court of California applied the new rules. Evidence of intoxication may show that the defendant did not actually form express malice, but not that he lacked the capacity to form it.
Case
People v. Flannel, (1979) 25 Cal.3d 668 (Supreme Court of California 1979)
Facts
The defendant shot and killed a man and claimed that he acted in self-defense. The trial court did not instruct the jury that an honest but unreasonable belief in the need for self-defense could reduce the crime to manslaughter.
Holding
An honest but unreasonable belief that deadly force is needed against imminent peril to life or great bodily injury negates malice aforethought. The killing is then voluntary manslaughter. The court still affirmed the conviction. The rule was not clearly stated when Flannel was tried, so the trial court had no duty to give the instruction without a request.
Why it matters
The origin of imperfect self-defense in California. It is a malice rule, not a justification: the defendant is still guilty of manslaughter.
Note
After July 2028: NextGen
From July 2028, NextGen tests Criminal Law and Procedure under general principles only. The Penal Code sections here matter only if the proposed California component (July 2029) is approved.
Exam tip
When the call is silent, apply general principles; do not cite the Penal Code. When the call names California, keep the analysis and add the section numbers. Use § 20 for concurrence, § 26 for mistake and unconsciousness, § 29.4 for intoxication, and § 25 for no diminished capacity.
Key notes
- 1.Pen. Code § 20: every crime needs a union of act and intent, or criminal negligence (concurrence).
- 2.Pen. Code § 26: mistake of fact, unconsciousness, accident and duress make a person incapable of committing a crime.
- 3.Pen. Code § 29.4: voluntary intoxication goes only to actual specific intent, premeditation, deliberation and express malice.
- 4.Pen. Code §§ 25, 28, 29: no diminished capacity; mental-disease evidence goes only to whether intent was actually formed.
- 5.Imperfect self-defense (Flannel): an honest, unreasonable belief in the need for deadly force reduces murder to voluntary manslaughter.
1.7 Review
This review has 5 multiple-choice questions in the MBE style. The real exam gives you 1.8 minutes for each question: 200 questions in two 3-hour sessions. Time yourself. For each question, find the actus reus first, then the mens rea the crime requires, then ask whether the facts join them: concurrence, causation and any mistake. Read the options only after you have predicted the answer. After the questions, the glossary lists the terms this chapter added; later chapters use them without explanation.
The examiners test this chapter inside questions about other crimes. The trap option in an omission question says “no duty because he was not the parent”. The trap in a mistake question says “the mistake was unreasonable” when the crime is specific intent. The trap in a causation question calls a negligent doctor a superseding cause. On an essay, these principles earn points as element headings under each crime, not as separate issues.
Practice · MBE
Shift + letter strikes an option
Answer: B
Practice · MBE
Shift + letter strikes an option
Answer: D
Practice · MBE
Shift + letter strikes an option
Answer: A
Practice · MBE
Shift + letter strikes an option
Answer: C
Practice · MBE
Shift + letter strikes an option
Answer: B
– A crime punishable by death or by imprisonment for more than one year; at common law, the most serious crimes.
– A crime punishable by a fine or by imprisonment for one year or less, usually in a local jail.
– A failure to act; criminal only where the law imposed a duty to act and the defendant could have acted.
– A regulatory crime with a light penalty, aimed at dangerous products or activities, for which courts accept strict liability.
– Deliberately avoiding confirmation of a fact one believes highly probable; treated as knowledge of that fact (MPC § 2.02(7)).
– A crime of preparation that is complete before the target crime occurs: solicitation, conspiracy and attempt.
– A former defense that a mental abnormality short of insanity reduced the crime; abolished in California by Penal Code section 25.
Chapter 2 builds on these principles: accomplice liability adds a second actor, and the inchoate offenses of solicitation, conspiracy and attempt punish conduct before the harm. Before you go on, be able to write from memory four things. They are the building blocks of a crime, the FIAT list of specific-intent crimes, the four MPC levels, and the two-step causation test. Chapter 3 then applies everything to homicide, the most tested crime on the essay day: murder appeared on 8 of the last 50 exams.
Key notes
Chapter summary
- 1.Default law is general principles; a quoted statute controls; California sections are cited only when the call names California.
- 2.Actus reus: a voluntary act, an omission backed by a legal duty, or knowing possession; never a status.
- 3.Mens rea: specific intent (FIAT), malice, general intent, strict liability; MPC purposely, knowingly, recklessly, negligently.
- 4.Mistake of fact must negate the required mental state; mistake of law is no defense except reliance, a knowledge element or Lambert notice.
- 5.Causation: but-for cause plus a foreseeable result; ordinary medical negligence and the victim’s frailty do not break the chain.
- 6.Solicitation and attempt merge into the completed crime; conspiracy does not at common law; corporations act through agents within the scope of employment.
Authorities in this chapter
End of chapter 1
Practice what you just read.
3 questions from this chapter, with an explanation for every option.