The decision is limited because it only applies to federal enclaves such as the District of Columbia.

It exercises concurrent jurisdiction to varying degrees with the states in many domestic federal enclaves.

Collectively, such federally administered areas that are not part of any state are called federal enclaves.

But at that time both states gave up land to create the federal enclave of the District of Columbia.

Nevertheless, Congress gradually authorized the enforcement of some state laws on federal enclaves.

Thus, in 1928, Congress made applicable to federal enclaves state laws governing wrongful death and personal injuries.

Federal government reports in 1956 and 1957 concluded that the states should have full concurrent jurisdiction on all federal enclaves.

The court relied in part on the fact that Congress had authorized the states to enforce many state laws on federal enclaves.

Under Evans, Congress has the power, if it chooses, to authorize the enforcement of all state laws on federal enclaves.

For many years, it was believed that "the vast majority" of National Forests were not federal enclaves.