The United States Supreme Court case of The United States v. Joseph H. Hernandez was a dispute over the ownership of land in Florida that had been granted to Hernandez by the Spanish government prior to its cession to the U.S. in 1819, and then subsequently sold by him after it became part of the U.S.. The court held that while Congress could not retroactively invalidate grants made before cession, they also did not have authority under existing treaties with Spain or any other law at that time to recognize those grants as valid titles for lands within their own territory; thus, Hernandez's title was void and he had no right to sell it afterwards without obtaining a new grant from Congress itself or some other competent authority empowered by them. This decision established an important precedent regarding property rights between nations during times of territorial transfer and has since become an oft-cited example when discussing such matters today

In the United States v. Joseph H. Hernandez, the Supreme Court was asked to decide whether a state court could issue an injunction against a federal officer in order to prevent him from executing his duties under federal law. The majority opinion held that such injunctions were not permissible because they would interfere with Congress’s exclusive power over national affairs and undermine its authority as established by the Constitution. However, Justice McLean dissented on this point, arguing that states had concurrent powers with Congress when it came to matters of local concern and thus should be allowed to exercise their own jurisdiction in certain cases involving federal officers if necessary for public safety or welfare. He further argued that allowing states some degree of control over these matters did not necessarily imply any disrespect for Congressional authority but rather served as a check on potential abuses of power by those same officers acting under color of law at the behest of Congress itself.