Page "Federal jurisdiction (United States)" Paragraph 3

Federal jurisdiction in this sense is important in criminal law because federal law, being based on a concept of enumerated powers, does not deal with crimes as comprehensively as the laws of any particular state.

To fill in any potential federal gaps, Congress has enacted the Assimilative Crimes Act (), which provides that any act that would have been a crime under the laws of the state in which a federal enclave is situated is also a federal crime.

Since most of these enclaves are occupied by the military, military law is especially concerned with these enclaves, especially the issue of establishing who has jurisdiction and what type of jurisdiction.

Specifically, in these enclaves, the federal government may have proprietary jurisdiction ( only the rights of any other landowner ), concurrent jurisdiction ( the right to legislate concurrently with the state government ), or exclusive jurisdiction over the land where an act was committed in order to establish jurisdiction over the actor.

This is not necessary for courts-martial involving military members subject to the Uniform Code of Military Justice as those military members are bound by the UCMJ regardless of their location.