John F. McKinney, plaintiff in error, brought a case against Manuel Saviego and his wife Pilar to the Supreme Court of the United States. The dispute was over land that had been granted by Congress to John's father-in-law, who then sold it to him. However, Manuel and Pilar claimed they owned the same land due to an earlier Spanish grant from 1790 which gave them title before John's purchase in 1843. The court found that since Spain had ceded Florida territory to the US in 1819 with no reservations or exceptions for private property rights like this one, any prior grants were invalidated and thus did not give Manuel and Pilar ownership of the disputed land; instead it belonged solely to John as per his valid purchase deed from 1843. Therefore he was entitled all legal benefits associated with owning said property including exclusive possession of it without interference from others such as Manuel and Pilar who falsely claimed ownership based on their invalid Spanish grant from 1790.

In the case of John F. McKinney v Manuel Saviego and Pilar, his wife, the dissenting opinion argued that a deed from an individual to himself was not valid under Spanish law. The majority had held that such a deed was valid because it had been accepted by both parties in good faith and with no intention to defraud anyone else. However, the dissent argued that this did not matter since Spanish law prohibited individuals from transferring property to themselves without authorization from another party or court order. Furthermore, they noted that even if there were some ambiguity in the language of the deed itself as to whether it constituted a transfer of title or merely an agreement between two parties for future consideration, then any doubt should be resolved against its validity due to public policy considerations which disfavor self-dealing transactions like this one.