In the case of Evans et al. v. Cornman et al., 1969, the U.S Supreme Court ruled that residents living on federal enclaves within a state have the right to vote in state elections. The case was brought forward by Robert E. Cornman and other residents of National Institutes of Health (NIH) property in Maryland who were denied their voting rights based on an interpretation that they weren't technically Maryland residents since they lived on federal land. The court unanimously decided against this interpretation, stating it violated equal protection under law as guaranteed by the Fourteenth Amendment because these individuals still had obligations and benefits associated with being Maryland citizens such as paying state taxes and receiving public services from the state.

In the dissenting opinion for Evans et al. v. Cornman et al., Justice Black argued that Maryland had a valid interest in limiting voting rights to those who were truly part of its political community, and not just residents within its geographical boundaries. He contended that the state should be able to decide whether people living on federal enclaves like NIH (National Institutes of Health) are sufficiently connected with the rest of Maryland's citizens to vote on matters affecting them all. According to him, these individuals did not pay property taxes or participate in local government affairs as other Marylanders do, hence they could be seen as less invested in state issues than regular inhabitants. Therefore, he believed it was reasonable for states to restrict their franchise accordingly.