In the 1918 case of O'Pry, Sole Surviving Descendant and Sole Heir of Kouns, etc., et al. v. United States, the U.S Supreme Court dealt with a dispute over land ownership in Louisiana between the descendants of an original grantee and the federal government. The plaintiff claimed that their ancestor had been granted land by Spain before it ceded Louisiana to France in 1800; therefore they were rightful owners under Spanish law which was still applicable at that time. However, when America acquired this territory through the Louisiana Purchase in 1803, it did not recognize these claims as valid due to lack of proper documentation proving Spanish approval for such grants or sales prior to its acquisition from France. The court ruled against O’Pry's claim stating that there was insufficient evidence supporting his assertion about his family’s entitlements under Spanish rule before American possession.

The dissenting opinion in the case of O'Pry, Sole Surviving Descendant and Sole Heir of Kouns, Etc., et al. v. United States argued that the majority's decision was incorrect because it failed to properly interpret and apply relevant legal principles related to property rights and inheritance law. The dissent believed that the plaintiff should have been recognized as the rightful heir to a piece of land originally granted by Spain before Louisiana became part of America. They contended that under Spanish law at the time, which they argue should still be applicable in this case, an illegitimate child could inherit from their father if acknowledged by him during his lifetime or through a will after his death - both conditions met by O’Pry’s ancestor Kouns according to presented evidence. Therefore, they concluded that denying O'Pry her claim contradicted established precedent regarding recognition of foreign laws concerning property rights when territories are acquired by U.S., thus setting a dangerous precedent for future cases involving similar circumstances.