Underwood v. McVeigh 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 who was being held in federal custody. The case arose when a prisoner, McVeigh, was arrested in the state of New York and held in federal custody. McVeigh then filed a petition for a writ of habeas corpus in the state court, arguing that he was being held in violation of his constitutional rights. The state court granted the writ, and the federal government appealed the decision 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 federal custody. The Court reasoned that the writ of habeas corpus was a federal remedy, and that the state court did not have the power to interfere with the federal government's authority to detain a prisoner. The Court also noted that the writ of habeas corpus was a remedy that could only be used to challenge the legality of a prisoner's detention, and not to challenge the merits of the underlying criminal charge. The Court's decision in Underwood v. McVeigh established that state courts do not have the authority to issue writs of habeas corpus to prisoners held in federal custody. This decision has been cited in numerous subsequent cases, and remains an important precedent in the area of federal habeas corpus law.

In Underwood v. McVeigh, the Supreme Court was asked to decide whether a contract between two parties that had been partially performed could be enforced by either party after one of them had died. The majority opinion held that the contract could not be enforced because it was impossible for both parties to perform their obligations under the agreement. Justice Field dissented from this decision and argued that contracts should generally be enforceable even if one of the contracting parties has passed away, as long as there is evidence showing what each party's obligations were under the agreement and how much performance had already taken place prior to death. He reasoned that allowing such contracts to remain in effect would provide greater certainty in commercial transactions and encourage people to enter into agreements with confidence knowing they will still have legal recourse if something happens before all terms are fulfilled.