Porter v. White was a United States Supreme Court case that addressed the issue of whether a state court could enforce a contract that was made in violation of a state statute. The case involved a contract between two parties, Porter and White, in which Porter agreed to pay White a certain amount of money in exchange for White's promise to convey certain real estate to Porter. The contract was made in violation of a state statute that prohibited the sale of real estate without the approval of the state court. The Supreme Court held that the state court could not enforce the contract because it was made in violation of the state statute. The Court reasoned that the state statute was a valid exercise of the state's police power and that the state court could not enforce a contract that was made in violation of the statute. The Court also noted that the state court could not enforce a contract that was made in violation of public policy. The Court's decision in Porter v. White established that state courts cannot enforce contracts that are made in violation of state statutes or public policy. This decision has been cited in numerous subsequent cases and has become an important precedent in contract law.

Justice Field delivered the dissenting opinion in Porter v. White, arguing that the majority's decision was contrary to both law and equity. He argued that a contract between two parties should be enforced as written unless there is evidence of fraud or mistake, which he did not believe existed in this case. Furthermore, he noted that if one party had been misled by another into signing an agreement without understanding its terms, then they would have grounds for relief; however, no such claim was made here. In addition to these points of contention with the majority opinion, Justice Field also disagreed with their interpretation of state statutes regarding contracts and mortgages as well as their conclusion on how those laws applied to this particular case. Ultimately Justice Field concluded his dissent by asserting that it was wrong for the court to interfere with a contract between two parties when neither party had requested any form of relief from it nor provided proof of fraud or mistake on either side's part.