text: consider the law respecting mens rea.in general,courts interpret criminal statutes to require that a defendant possess a mens rea,or guilty mind,as to every element of an offense.see elonis united states,slip,at.that is so even when the statute by its terms does not contain any demand of that kind.united states video.in such cases,courts read the statute against a background rule that the defendant must know each fact making his conduct illegal.staples united states.or otherwise said,they infer,absent an express indication to the contrary,that congress intended such a requirement.