Vetterlein v. Barnes was a United States Supreme Court case that addressed the issue of whether a state court could enforce a contract that was made in another state. The case involved a contract between two parties, Vetterlein and Barnes, in which Vetterlein agreed to pay Barnes a certain amount of money for the sale of a piece of property. The contract was made in the state of Virginia, but Barnes later sued Vetterlein in the state of Maryland for non-payment. The Supreme Court held that the state of Maryland could not enforce the contract because it was made in another state. The Court reasoned that the contract was made in Virginia and was therefore subject to the laws of that state. The Court also noted that the contract was not made in Maryland and therefore the state of Maryland had no authority to enforce it. The Court's decision in Vetterlein v. Barnes established the principle that a state court cannot enforce a contract that was made in another state. This principle is still followed today and is an important part of contract law.

In Vetterlein v. Barnes, the Supreme Court was asked to decide whether a contract between two parties could be enforced even though it had been made in violation of a state statute. The majority opinion held that the contract should not be enforced because it violated public policy and thus was voidable at the option of either party. Justice Field dissented from this decision, arguing that there is no general rule prohibiting contracts which violate statutes; rather, each case must be decided on its own merits based on considerations such as whether or not enforcement would lead to an unjust result or encourage further violations of law. He argued that since neither party here had acted fraudulently or with bad faith intent, enforcing their agreement would not lead to any injustice and therefore should have been allowed by the court.