This Supreme Court case involved the United States as appellants and Christian Roselius, Abial D. Crossman, William E. Liveridge, Francois B. D'Autuin, Benjamin C. Howard, John Spear Smith, Brantz Mayer and John Gibson and R.R Gurley as executors of John McDonogh deceased as respondents in a dispute over land titles in Louisiana that were granted by Spain prior to the Louisiana Purchase of 1803 but not confirmed by Congress until 1845-1846 after the state had been admitted into the Union in 1812-1813 . The issue was whether or not these pre-purchase grants could be recognized under federal law since they had never been approved by Congress before being sold to private individuals who then sought confirmation from Congress for their title claims after purchase? The Supreme Court held that such grants must be respected if valid according to Spanish laws at time of grant even though they may have occurred prior to transfer of ownership from Spain to U.S., thus confirming rights acquired through bona fide purchases made with reasonable belief that title was good despite lack of Congressional approval beforehand

In the United States v. Roselius et al., the Supreme Court was tasked with determining whether a Louisiana state court had jurisdiction to hear a case involving an estate dispute between two parties, one of whom resided in Maryland and the other in Louisiana. The majority opinion held that because both parties were citizens of different states, federal law gave exclusive jurisdiction to federal courts over such cases. However, Justice McLean dissented from this ruling on the grounds that it violated principles of comity among states by allowing one state's laws to be enforced against another without its consent or participation. He argued that while Congress may have intended for certain matters related to interstate disputes to be heard exclusively by federal courts, they did not intend for those decisions to override established principles of comity among states which allowed them each their own autonomy when dealing with legal issues within their borders. Therefore, he concluded that since neither party objected nor requested removal from state court proceedings and no constitutional issue was raised during trial proceedings there should have been no interference from the Supreme Court as it would violate these long-established principles governing relations between sovereigns