If someone commits a crime, does it matter whether or not they intended to commit a crime? Should they still be found guilty even if they didn't know they were breaking the law? These may sound like odd questions, but the concept they describe has long been a cornerstone of criminal justice.
Traditionally, a person was said to have committed a crime if they committed an illegal act and if they did so with criminal intent. The latter concept is known as "mens rea," which loosely translates as "guilty mind." While many crimes require prosecutors to prove mens rea, there are many other criminal statutes that do not. In other words, the act itself is sufficient to secure a conviction.
As an example, consider a case that made headlines several years ago. In 2009, a retired Idaho man and his son decided to dig for Native American arrowheads at a campground. Collecting these artifacts was a hobby for the man.
They didn't find any arrowheads, nor did they know that what they were doing was illegal. But they were on federal land, and a 1979 law meant to protect archeological resources made it illegal to take any artifacts found on federal land without obtaining a permit. The law does not consider mens rea, and violators can be imprisoned for up to two years. To be safe, each of the men agreed to a plea deal that included probation and a significant fine.
In late 2015, federal lawmakers introduced legislation that would essentially require prosecutors to prove mens rea in any cases where the text of a criminal statute does not "specify a state of mind." If passed, this legislation would greatly impact the way that many federal crimes were prosecuted.
Like all legislation, these mens rea reforms are controversial, and some believe such changes would ultimately do more harm good. At the very least, we must hope that mens rea remains a frequent topic of discussion and debate.