Shields v. Schiff was a United States Supreme Court case that dealt with the issue of whether a contract between two parties was valid. The case involved a dispute between two parties, Shields and Schiff, over a contract for the sale of a piece of real estate. Shields had agreed to purchase the property from Schiff for a certain amount of money, but Schiff later refused to accept the payment and refused to transfer the property to Shields. Shields then brought a lawsuit against Schiff, claiming that the contract was valid and that Schiff was obligated to transfer the property to him. The Supreme Court ultimately ruled in favor of Shields, finding that the contract was valid and that Schiff was obligated to transfer the property to Shields. The Court held that the contract was binding and enforceable, and that Schiff was not entitled to refuse to transfer the property to Shields. This ruling established that contracts between two parties are binding and enforceable, and that parties cannot simply refuse to fulfill their obligations under a contract.

In Shields v. Schiff, the Supreme Court was asked to decide whether a contract between two parties could be enforced if it had been made in violation of a state law prohibiting contracts for the sale of lottery tickets. The majority opinion held that such contracts were unenforceable and void. Justice Field dissented from this decision, arguing that while states have the power to regulate certain activities within their borders, they do not have authority over private contractual arrangements which are valid under federal law. He argued further that since there is no federal statute prohibiting such contracts, then any state laws attempting to do so would be unconstitutional as an infringement on Congress' exclusive powers granted by Article I Section 8 of the Constitution. Furthermore, he noted that even if there was some public policy reason behind enforcing these statutes (such as discouraging gambling), this did not justify overriding established principles of contract law which protect individuals who enter into legitimate agreements with one another without intending any harm or fraud upon either party involved