The WSJ has a lengthy piece about the proliferation of federal criminal laws,  and tells the story of a number of people who unknowingly violated obscure federal criminal statutes–many of which lack a mens rea requirement–including history buff Eddie Leroy Anderson, who violated the 1979 Archaeological Resources Protection Act by removing arrowheads from federal land without a permit.

Should society hold people accountable for violating laws–without any mens rea–that few if any experts know exist? Judge Posner addressed just this point in his dissent in United States v. Wilson:

We want people to familiarize themselves with the laws bearing on their activities. But a reasonable opportunity doesn’t mean being able to go to the local law library and read Title 18. It would be preposterous to suppose that someone from Wilson’s milieu is able to take advantage of such an opportunity. If none of the conditions that make it reasonable to dispense with proof of knowledge of the law is present, then to intone “ignorance of the law is no defense” is to condone a violation of fundamental principles for the sake of a modest economy in the administration of criminal justice.

Even if Anderson were to go to the local law library, and read through the entirety of Title 18, it’s unlikely he would be able to learn all of the federal laws. As the WSJ piece points out, several attempts at cataloguing all federal crimes, including violations of regulations that carry criminal penalties, by the Department of Justice, the American Bar Association, and others have failed.

Counting them is impossible. The Justice Department spent two years trying in the 1980s, but produced only an estimate: 3,000 federal criminal offenses.

The American Bar Association tried in the late 1990s, but concluded only that the number was likely much higher than 3,000. The ABA’s report said “the amount of individual citizen behavior now potentially subject to federal criminal control has increased in astonishing proportions in the last few decades.”  . . .  Today, there are an estimated 4,500 crimes in federal statutes, according to a 2008 study by retired Louisiana State University law professor John Baker.

So if the smartest legal minds are unable to list all of the federal crimes, how can we hold people like Anderson culpable for violation of essentially unknown federal laws that lack any intent requirement? Is Posner right to say we are condoning a violation of a fundamental principle of justice for the sake of a “modest economy in the administration of criminal justice”? Is ignorance of the law no longer a valid excuse? If so, what would the remedy be?

Cross-Posted at ConcurringOpinions.com.