Jaeger v. Moore 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, Jaeger and Moore, in which Jaeger agreed to pay Moore a certain amount of money for the sale of a piece of property. The contract was made in violation of a state statute that prohibited the sale of property without a license. 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 without proper consideration. The Court's decision in Jaeger v. Moore established that a state court could not enforce a contract that was made in violation of a state statute. This decision has been cited in numerous cases since then and has been used to support the idea that a state court cannot enforce a contract that is made in violation of the law.

Justice Harlan delivered the dissenting opinion in Jaeger v. Moore, a case concerning whether or not an individual could be held liable for failing to pay taxes on property that was transferred from one person to another without consideration. Justice Harlan argued that the majority's decision failed to consider the fact that there had been no actual transfer of title between parties and thus, no taxable event occurred. He further noted that if such a tax were imposed it would constitute an unconstitutional taking of private property without due process of law as guaranteed by the Fifth Amendment. Additionally, he argued that since this was a state-level dispute, it should have been decided according to state laws rather than federal ones; however, even under state law there had been no transfer of title and therefore any attempt at taxation would be invalid. In conclusion, Justice Harlan believed that imposing such a tax violated both constitutional principles and existing legal precedent and should not stand as part of U.S Supreme Court jurisprudence