Ignorance of the Law May Be an Excuse

By Thomas Seigel, Attorney and Former Federal Prosecutor
Ignorance of the law can be an excuse in two very narrow situations.

Most people are familiar with the legal principle that ignorance of the law is no excuse. This age-old rule prevents individuals from avoiding prosecution by claiming that they did not know their conduct was illegal. In most cases—such as murder, theft, assault, and arson—it is obvious why defendants should not be able to claim ignorance as a defense. But ignorance can, under certain limited circumstances, provide a viable defense to a criminal charge.

Let’s look at those circumstances more closely.

The Need for Public Notice

State and federal governments cannot pass secret criminal laws and then prosecute an unwary offender. (This only happens in totalitarian regimes and in the novels of Franz Kafka.) Criminal laws must be enacted through a public process in the state or federal legislatures, and those laws must be published in accessible places such as official volumes containing the penal code, or on a government website.

Sometimes the law criminalizes behavior that might be lawful in some places. For example, it might be okay to park along the shoulder of a particular highway, but in some stretches, the highway department posts “No Parking” signs to alert drivers that here, no parking is allowed. These signs give fair warning; without them, drivers cannot be expected to know the rule, and would have a good defense if they are ticketed.

Because our government has long-established procedures for making laws known, insufficient public notice is rarely an available defense. However, where defendants are charged with violating a brand new law that criminalizes behavior that is perfectly lawful in other places, those individuals may be able to assert their ignorance as a defense. The availability of the defense, however, will turn not only on a defendant’s lack of knowledge and the government’s lack of notice, but also on the particular wording of the criminal law in issue.

Specific Intent Crimes

Criminal statutes often require a defendant to have a particular state of mind. Some crimes, such as statutory rape, require no state of mind and are punishable no matter what the offender thought. Other crimes require a defendant to have acted with reckless disregard for the safety of others. For example, a reckless state of mind might be required for a charge of involuntary manslaughter. Where, however, criminal laws require that a defendant must have acted “willfully” when violating the law, a defendant unaware of the legal prohibition may be able to claim ignorance as a defense to the charge.

For example, consider a law that requires a business owner to file a certain tax form related to the business. The law says that willfully failing to do so is an offense. In this situation, the owner’s ignorance of the filing requirement might well be a good defense. In fact, it would be the prosecutor’s burden to prove willfulness in demonstrating that the owner purposefully avoided filing the tax form.

Sometimes, however, “willfulness” relates only to the defendant’s state of mind during the commission of the act—as the case may be with crimes like witness tampering or child endangerment—and has nothing to do with the defendant’s knowledge of the applicable criminal law. (For example, a defendant might have no idea that contacting and conversing with an adverse witness can be a criminal act; but that is no excuse if the prosecution can show that the conversations affected the witness.) Your attorney will be able to advise you on whether a willfulness requirement in the charge in your case might allow for a defense of ignorance.

Questions to Ask My Lawyer

  • How long has the criminal law in my case been on the books?
  • Is my alleged conduct lawful in other places?
  • Does the crime charged involve technical knowledge?
  • Does the criminal statute require willfulness?
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