On June 27, the U.S. Supreme Court expanded the scope of the government's burden of proof of a defendant's mental state, or mens rea. The Supreme Court held that in a statute that provided an exception or exemption to prosecution, that is a clause stating "except as authorized," the government must now prove beyond a reasonable doubt that a defendant knew that he did not fall within the scope of that exception. Although the case related to a federal criminal statute prohibiting the dispensing or distribution of controlled substances by a physician, the ruling can be applied to myriad criminal statutes that carve out exceptions or exemptions to prosecution. This article explains the Supreme Court's decision and focuses on the ramifications as it pertains to other criminal statutes. It also raises questions regarding the reasonableness standards of the exclusionary rule under United States v. Leon, 468 U.S. 897 (1984).