Walker v. Villavaso was a United States Supreme Court case that addressed the issue of whether a state court could enforce a contract made in another state. The case involved a contract between two individuals, Walker and Villavaso, in which Walker agreed to pay Villavaso a certain sum of money for the purchase of a slave. The contract was made in Louisiana, but Walker later moved to Mississippi and refused to pay the money. Villavaso then sued Walker in a Mississippi court. The Supreme Court held that the Mississippi court had no jurisdiction to enforce the contract because it was made in Louisiana. The Court reasoned that the contract was made in Louisiana and was therefore subject to the laws of that state. The Court also noted that the contract was not a matter of public policy, and therefore the Mississippi court had no authority to enforce it. The Court's decision in Walker v. Villavaso established the principle that a state court cannot enforce a contract made in another state. This principle has been applied in numerous cases since then, and it remains an important part of contract law today.

In Walker v. Villavaso, the Supreme Court was tasked with determining whether a state court had jurisdiction to hear a case involving two citizens of different states. The majority opinion held that it did not have such authority and reversed the decision of the lower court. Justice Field dissented from this ruling, arguing that under Article III of the Constitution, Congress has given state courts concurrent jurisdiction over cases between citizens of different states when those cases involve matters arising within their respective jurisdictions. He further argued that since both parties in this case were domiciled in Louisiana at the time they entered into their contract, any dispute arising out of said contract should be heard by a Louisiana court as it is well within its jurisdiction to do so. Therefore he concluded that there was no error on behalf of either party or on behalf of the lower court's decision and thus voted against reversing it.