Two visions of American criminal law have emerged. The first vision is that criminal law is statutory and posits that legislatures, not courts, draft substantive criminal law. The second vision, like the first, begins with legislative supremacy, but it ends with democratic dysfunction. On this view, while contemporary American criminal law is statutory in theory, in practice, American legislatures badly draft and maintain criminal codes. This effectively delegates the “real” drafting of criminal law to prosecutors, who form the law through their charging decisions.
This Article offers a third vision: that modern American criminal law is primarily conventional. That is, much of our criminal law is defined by unwritten common-law-like norms that are widely acknowledged and generally respected, and yet are not recognized as formal law enforceable in courts. This Article makes three contributions. First, it argues that criminal law conventions exist. Second, it explains how nonlegal checks on prosecutorial power bring about criminal law conventions. Third, it provides an account for how legislatures and courts should respond to a criminal law heavily comprised of norms that rely primarily on nonlegal sanctions for their enforcement.