In The United States, Appellants v. The Heirs of Joseph Delespine and Others, Appellees, the Supreme Court was asked to decide whether or not a certain parcel of land in Florida belonged to the United States or to private individuals. At issue was an 1821 grant from Spain that had been made before Florida became part of the United States. After examining evidence presented by both sides, including Spanish documents and testimony from witnesses who had lived in Florida during Spanish rule, the court concluded that title did indeed belong to private individuals rather than the government. In its opinion it noted that while Congress could pass laws affecting public lands within its borders after acquiring them through treaty with foreign powers such as Spain, it could not retroactively invalidate grants already made prior to acquisition without due process of law.

In this case, the United States argued that it had a right to reclaim land in Louisiana which was originally granted by Spain. The Heirs of Joseph Delespine and others countered that they were entitled to the property as purchasers from private individuals who had acquired it from France after its purchase of Louisiana. The Supreme Court ultimately sided with the appellees, finding that although Spain may have initially held title to the land before ceding it to France, once France took possession of Louisiana all Spanish titles became invalidated and could not be reclaimed by any other nation or individual. Furthermore, since no one else had any claim on the property when it was purchased by private individuals from France, those purchases should be respected and upheld under U.S law. Thus, despite arguments made by both parties regarding their respective rights over this particular parcel of land in question, only those persons who bought directly from French sources could legally own or possess such lands within U.S territory at present time according to Supreme Court ruling in this case