Hall v. Law 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, Hall and Law, in which Hall agreed to pay Law a certain sum of money in exchange for Law's services. The contract was made in violation of a state statute that prohibited such contracts. 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 had the right to protect its citizens from contracts that were made in violation of the law. The Court also noted that the state had the right to protect its citizens from contracts that were made in violation of public policy. The Court's decision in Hall v. Law established that state courts could not enforce contracts that were made in violation of state statutes. This decision has been cited in numerous cases since then and has been used to support the idea that state courts should not enforce contracts that are made in violation of the law.

In Hall v. Law, the Supreme Court was asked to decide whether a contract between two parties that had been partially performed could be enforced by one of them against the other. The majority opinion held that it could not, as there was no consideration for such an agreement and thus it violated public policy. Justice Field dissented from this decision on the grounds that while contracts without consideration are generally unenforceable, in cases where part performance has already occurred they should be enforceable if both parties have benefited from their arrangement and neither party is at fault or has acted fraudulently or unconscionably. He argued further that since partial performance had taken place here, with each party receiving something of value from the other, enforcement would serve justice better than non-enforcement would.