For many but not all crimes, the prosecution must prove not only that the defendant carried out certain acts but also that they had a certain mental state. This is often known as the “mens rea” (“guilty mind”) element, and it prevents people from being punished when their intentions were innocent. When a prosecutor is trying to prove intent or another mental state, they may present evidence showing that a defendant had a motive to commit the crime. Conversely, a defendant may try to defeat a charge by showing that they did not have a motive to commit the crime. However, having a motive is not a required element of a crime.
Amnesia or another form of memory loss is not a defense because failing to remember a crime does not mean that the defendant did not intend to commit it. The defendant’s mental state at the time of committing the crime is what determines guilt or innocence. Memory loss can support an argument that the defendant is not competent to stand trial, and a judge can consider it when determining a defendant’s sentence.
Ordinary negligence (carelessness) can lead to liability in a civil case, such as a personal injury claim. However, it generally will not support a criminal conviction. Criminal negligence goes beyond ordinary negligence to a state of mind more like recklessness. If a defendant disregarded a significant risk to the safety of others, even if they did not intend to cause harm, this may lead to criminal liability on the basis of recklessness, gross negligence, or a similar concept. The jury must make a fact-specific decision on how far the defendant’s conduct fell short of the standard of a reasonable person in the community.
Often, a defendant must have committed a crime knowingly or intentionally. The intent requirement may be attached to each element of a crime, or only to certain elements. Sometimes the mental state requirement involves only a general intent. This means that the defendant had the intent to commit certain acts but not necessarily the intent to achieve a certain result.
In specific intent crimes, by contrast, the prosecution must prove that the defendant had a certain purpose for committing the acts. They must have intended to achieve a specific result, which requires more than just being aware that the result might occur. It may be hard to discern whether a law requires general intent or specific intent, but specific intent may arise when a statute refers to purpose or a mental state higher than knowing and voluntary. You can consult an attorney for guidance on whether a statute likely requires general or specific intent.
A conviction of a serious crime sometimes will require proof of malice or willfulness. Malice may be used as a synonym for intent or knowledge, but sometimes it represents a higher level of culpability. It may involve an intent or willingness to endanger the lives of others. Willfulness also may be used as a synonym for intent or knowledge. However, sometimes it can require the prosecution to prove that the defendant not only intended to commit the acts that constituted the crime but also specifically intended to break the law.
Mistakes of Fact and Mistakes of Law
Except in some situations involving willfulness, as discussed above, a mistake of law usually does not offer a defense to a crime. This means that a defendant can be convicted regardless of whether they know that they are breaking the law, as long as they intentionally commit the acts that comprise the crime. Otherwise, people would be rewarded for remaining ignorant of the law.
On the other hand, a mistake of fact may serve as a defense to a crime. This happens when someone did not perceive the situation as it was in reality. If they had correctly understood the circumstances, they likely would not have acted as they did. People should not be punished for making an honest mistake.
Strict Liability Crimes
Certain crimes do not require proof of a mental state element. This means that a defendant may be convicted even if their intentions were innocent. Strict liability may be appropriate when the interest of the public in preventing or punishing certain behavior trumps the moral concern over punishing someone who did not intend to cause harm. Some liquor laws may impose strict liability, such as a ban on selling alcohol to minors.
Most strict liability offenses are relatively minor, but there are some exceptions, such as statutory rape. Many states impose severe penalties on someone who has sexual relations with a minor under a certain age, even if the minor lied about their age and even if the defendant had a reasonable belief that the minor had reached the age of consent.