State and federal courts have long engaged in intersystemic adjudication,' interpreting and applying the constitutions, lawS, and regulations of one another's governments. Perhaps the best known instance in the civil litigation realm occurs with federal diversity jurisdiction, where, as a result of Erie Railroad Co. v. Tompkins, federal courts resolve federal civil claims on the basis of state substantive laws.
With criminal laws, however, the phenomenon has been and remains less apparent. This is in significant part due to the principle that such laws embody sovereign normative preferences, susceptible to neither enforcement nor jurisprudential control by other governments. Nevertheless, some degree of interaction has always been in evidence. Indeed, during the nation's formative years, states at times exercised concurrent jurisdiction over federal criminal matters, and while federal jurisdiction is exclusive today, the prospect of concurrent criminal jurisdiction persists." Moreover, state criminal laws can figure in federal criminal prosecutions. Under the Assimilative Crimes Act ("ACA"), for instance, since 1825 state laws have provided the bases for federal prosecutions when misconduct in federal enclaves is not expressly addressed by the U.S. Code. In such situations, the federal government "assimilates" state criminal law, in effect adopting it as federal law.
Wayne A. Logan,
Erie and Federal Criminal Courts,
63 Vanderbilt Law Review
Available at: https://scholarship.law.vanderbilt.edu/vlr/vol63/iss5/2