8.4 Mistake of Fact, Mistake of Law & Concurrence

Mistake of Fact, Mistake of Law & Concurrence

1. Mistake of Fact: Specific Intent vs. General Intent

The Doctrinal Mechanics

Mistake of fact is not an affirmative defense in the traditional sense; rather, it is a defense because it negates the mental state (mens rea) required for the commission of the charged crime. The validity of the defense depends strictly on the category of the offense:

Does Mistake Negate Mens Rea?
├── Specific Intent Offense ──▶ ANY Honest Mistake (Reasonable OR Unreasonable) Excuses Liability
├── General Intent Offense  ──▶ ONLY an Honest AND REASONABLE Mistake Excuses Liability
├── Malice Offense          ──▶ ONLY an Honest AND REASONABLE Mistake Excuses Liability
└── Strict Liability        ──▶ NEVER a Defense (Mistake of Fact Completely Irrelevant)

The FYLSE "Claim of Right" Trap in Theft Crimes

Larceny requires the trespassory taking and carrying away of the personal property of another with the specific intent to permanently deprive the owner thereof (animus furandi). If a defendant takes an item under an honest, good-faith belief that the property belongs to them, or that they have a legal right to take possession of it, the defendant lacks the specific intent to steal.

• Exam Application: Even if the defendant's belief was completely foolish, irrational, or negligent (e.g., taking an umbrella that looks completely different from their own, or seizing a television from a debtor under the erroneous belief that self-help repossession without a court order is legal), the honest belief negates specific intent, barring a conviction for larceny or robbery.

---

2. Mistake of Law & The Advice of Counsel Trap

The Baseline: Ignorantia Juris Non Excusat

The ancient common-law rule ignorantia juris non excusat (ignorance of the law is no excuse) remains a pillar of criminal jurisprudence. A defendant cannot avoid criminal liability by demonstrating that they were unaware that their conduct was prohibited by the penal code, or that they misunderstood the legal scope of a criminal statute, even if their ignorance was entirely reasonable and held in good faith.

The Three Narrow Recognized Exceptions

A mistake of law will excuse a defendant only under three highly specific, narrow exceptions:

1. Statute Not Published or Reasonably Made Available: Due process guarantees fair notice. If a penal statute or administrative regulation was not published, promulgated, or reasonably made available to the public prior to the defendant's conduct, prosecution is unconstitutional (Lambert v. California, 355 U.S. 225 (1957)).
2. Reasonable Reliance on an Official Statement of Law: The defendant engaged in conduct in reasonable reliance upon an official, authoritative statement of the law afterward determined to be invalid or erroneous, contained in:
   • An official statute or judicial decision of the highest appellate court in the jurisdiction;
   • An official written interpretation issued by the public officer or administrative agency charged by law with enforcing or interpreting the statute (e.g., a formal written opinion issued by the State Attorney General).
3. Collateral Mistake of Law Negating Specific Mens Rea: Where the definition of a specific intent offense incorporates a non-penal legal standard, an honest mistake concerning that collateral civil law negates the specific intent required by the penal statute (e.g., a defendant who fails to file a tax return because of an honest, good-faith misunderstanding of complex federal tax regulations lacks the required "willfulness" for criminal tax evasion).

The Fatal FYLSE Trap: Reliance on Private Legal Counsel

Examiners constantly test examinees with fact patterns where a defendant consults a licensed, experienced private attorney, receives explicit formal written advice that a planned business operation is completely lawful under state criminal statutes, relies on that advice in good faith, and is subsequently arrested.

• THE HARD RULE: Reliance on the advice of a private attorney is NEVER a valid defense of mistake of law. Private attorneys are not government officials, and their legal opinions do not constitute an official statement of the law. The defendant acts at their own peril.

---

3. The Concurrence Principle

Temporal and Motivational Coincidence

To establish criminal guilt, the prosecution must prove the concurrence principle: the required mental state (mens rea) must actuate and coincide temporally with the physical conduct (actus reus). The mental state must be the moving force that triggers the physical act that causes the prohibited harm.

Recurring Concurrence Traps on the FYLSE

1. Antecedent Intent Abandoned Before the Act: A defendant forms a premeditated intent to murder their business rival, purchases a gun, but subsequently experiences remorse and abandons the murder plan entirely. Three weeks later, while driving safely and obeying all traffic laws, the defendant accidentally strikes a pedestrian who darted into traffic. The pedestrian is discovered to be the business rival. The defendant is not guilty of murder because the prior intent did not actuate or coincide with the accidental physical collision.
2. Subsequent Intent Formed After the Physical Act: A defendant accidentally backs his car out of a driveway and strikes a pedestrian, causing fatal head trauma. Upon exiting the vehicle, the defendant discovers that the deceased pedestrian is his bitter mortal enemy, and the defendant dances with joy and proclaims his happiness that the victim is dead. The defendant is not guilty of murder because the malicious intent arose after the physical actus reus had already occurred.
3. The Continuing Trespass Exception in Larceny: A narrow common-law exception exists for theft crimes under the doctrine of continuing trespass. If a defendant takes another's personal property without permission (a trespassory taking) but without an initial intent to steal (e.g., intending only to borrow the item temporarily), and later decides to keep the property permanently, the original trespassory taking is deemed to "continue" in the eyes of the law until the intent to permanently deprive is formed, thereby satisfying the concurrence requirement for common-law larceny.