Foley v. Smith was a United States Supreme Court case that dealt with the issue of whether a state court had the authority to issue a writ of habeas corpus to a prisoner held in a federal prison. The case arose when a prisoner, Foley, was held in a federal prison in the state of New York. Foley sought a writ of habeas corpus from the state court, which was denied by the state court on the grounds that it lacked jurisdiction over federal prisoners. Foley then appealed to the Supreme Court. The Supreme Court held that the state court did not have the authority to issue a writ of habeas corpus to a prisoner held in a federal prison. The Court reasoned that the writ of habeas corpus was a federal prerogative, and that the state court lacked the authority to interfere with the federal government's power to imprison individuals. The Court also noted that the writ of habeas corpus was a fundamental right, and that the state court should not be allowed to interfere with the federal government's power to imprison individuals. In conclusion, the Supreme Court held that the state court did not have the authority to issue a writ of habeas corpus to a prisoner held in a federal prison. The Court reasoned that the writ of habeas corpus was a federal prerogative, and that the state court lacked the authority to interfere with the federal government's power to imprison individuals.

In Foley v. Smith, the Supreme Court was asked to decide whether a contract between two parties that included an agreement not to sue each other in court could be enforced. The majority of the justices held that such contracts were valid and enforceable, but Justice Field dissented from this opinion. He argued that while it is true that people should generally be allowed to make agreements about how they will resolve disputes without involving courts, there are certain circumstances where public policy demands otherwise. In particular, he noted that if one party has been wronged by another then they should have access to legal remedies regardless of any prior agreement between them; allowing such contracts would effectively deny them justice and thus violate public policy principles which must take precedence over private contractual arrangements in some cases.