The Mistake of Law Defense and an Unconstitutional Provision of the Model Penal Code

Abstract

At common law, a defendant’s mistaken belief about the law was no defense, even if that mistake resulted from reasonable reliance on governmental advice. Thus, if a prosecutor or police officer erroneously advised that certain conduct was legal, the government was free to prosecute anyone following that advice. In the mid-1950s, two separate legal doctrines altered the common-law rule. First, the American Law Institute’s Model Penal Code included a mistake of law defense; a version of this defense was adopted in many states. A few years later, the Supreme Court held that the Constitution prohibited conviction in those circumstances; the Court cited neither the Model Penal Code nor related criminal jurisprudence, instead relying solely on due process principles. Now, in many states, two distinct mistake of law defenses cover the same situation, one based on the Constitution and another based on the Model Penal Code. However, while the Model Penal Code defense never applies when the constitutional defense does not, in many cases the Model Penal Code allows conviction when the Constitution granted the defense based on oral advice by government actors, but the Model Penal Code, as enacted in several states, allows the defense only for written advice. Similarly, the Supreme Court has granted the defense for strict liability crimes, but some statutes deny the defense in such cases. There is never a reason for a defendant to raise the statutory defense; the constitutional defense is better or at least as good in all cases. But many courts and lawyers do not recognize that there are two defenses, one offering less coverage than the other. As a result, many defendants are convicted after their claims are rejected under a statute when they might have been acquitted had they raised the argument directly under the Constitution. Ironically, then, a law intended to protect people from government deception has itself become a source of government deception. This is unjust. Courts, counsel, legislatures, and the American Law Institute should reconcile the defenses, and ensure that cases are decided based on applicable law rather than because of lawyers’ or judges’ mistakes about the law.

Keywords: mistake of law; due process; model penal code