Malum Prohibitum

"If it were up to me, I’d find it a violation of the due process clause to treat violation of regulatory statutes as a felony. Historically, only the most serious crimes — typically carrying the death penalty — were felonies.  Nowadays, though, we designate all sorts of trivial crimes, such as possessing an eagle feather, as felonies. This has the effect of empowering police and prosecutors at the expense of citizens, since it’s easy to find a felony if you look hard enough, and few citizens have the courage of a veteran like Cort, who went to trial anyway. Most will plead to something."

Glenn Reynolds: How gun laws put the innocent on trial