Felix Frankfurter

“ Considerations of hardship often lead courts, naturally enough, to attribute to a statute the requirement of a certain mental element some consciousness of wrongdoing and knowledge of the law's command-as a matter of statutory construction. ”

“ The present laws of the United States and of the forty-eight States are thick with provisions that command that some things not be done and others be done, although persons convicted under such provisions may have had no awareness of what the law required or that what they did was wrongdoing. The body of decisions sustaining such legislation, including innumerable registration laws, is almost as voluminous as the legislation itself. ”