The United States Supreme Court case of The United States v. Bernardo Segui involved the question of whether a foreign-born person who had been naturalized in one state could be prosecuted for a crime committed in another state. In this case, Segui was charged with larceny and convicted by the Circuit Court for East Florida. He appealed his conviction to the Supreme Court on grounds that he was not subject to prosecution because he had been naturalized as an American citizen in Louisiana prior to committing the offense in Florida. The court held that although Congress has exclusive power over immigration and naturalization, it does not have authority over criminal prosecutions within individual states; therefore, each state is free to determine its own laws regarding citizenship rights and obligations within its borders. As such, Segui's conviction was upheld since he did not possess any special privileges due to his status as a naturalized citizen from another state when committing crimes within Florida's jurisdiction.

In The United States v. Bernardo Segui, the Supreme Court was tasked with determining whether a Spanish subject who had been residing in Florida since 1821 and had married an American citizen could be considered an alien or a naturalized citizen of the United States. The majority opinion held that Segui was not entitled to citizenship because he did not meet any of the conditions for naturalization as outlined by Congress at that time. Justice McLean dissented from this decision, arguing that Segui should be granted citizenship due to his long-term residence in Florida and marriage to an American citizen. He argued that under these circumstances, it would be unjust for him to remain stateless without being able to enjoy all of the rights afforded by U.S. citizenship such as protection against foreign governments and access to public lands within U.S territories which were otherwise unavailable without proof of nationality status