In the United States Supreme Court case of The United States v. William Marvin, the appellant argued that a contract between himself and an Indian tribe was invalid due to its violation of federal law. Specifically, it was alleged that the contract violated provisions in a treaty which prohibited Indians from entering into contracts with non-Indians without approval from Congress or other authorized government officials. In response, Marvin argued that he had acted in good faith and did not know about any such restrictions when he entered into the agreement with the tribe. Ultimately, however, after considering both sides’ arguments on appeal, the Supreme Court held that since no authorization for this particular contract existed under federal law at time it was made then it must be declared void as being contrary to public policy.

In the United States v. William Marvin, the Supreme Court was tasked with deciding whether a contract between two parties could be enforced if it had been made in violation of an existing law. The majority opinion held that such contracts were void and unenforceable, while Justice McLean dissented from this decision. He argued that although it is true that laws should be obeyed and upheld, there are also principles of justice which must be respected when considering contractual obligations between two parties. In his view, enforcing a contract would not necessarily mean condoning or encouraging illegal behavior; rather, it would simply recognize the rights of both parties to receive what they bargained for under their agreement. Furthermore, he noted that allowing courts to refuse enforcement on these grounds might lead to uncertainty about other types of contracts as well as create opportunities for fraud and injustice against innocent individuals who have no knowledge or control over any violations committed by either party involved in their transaction.