Lehnbeuter v. Holthaus 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 a federal prison. The case arose when a prisoner, Lehnbeuter, was held in a federal prison in Wisconsin. Lehnbeuter sought a writ of habeas corpus from the Wisconsin state court, which the court granted. The United States government then 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 a federal prison. The Court reasoned that the power to issue writs of habeas corpus was a power reserved to the federal government, and that the state court did not have the authority to interfere with the federal government's power. The Court also noted that the state court's decision was in conflict with the federal government's power to regulate the federal prison system. The Court's decision in Lehnbeuter v. Holthaus established that state courts do not have the authority to issue writs of habeas corpus to prisoners held in federal prisons. This decision has been cited in numerous subsequent cases, and has been used to support the idea that the federal government has exclusive authority over the federal prison system.

In Lehnbeuter v. Holthaus, the Supreme Court was tasked with determining whether a contract between two parties could be enforced despite its illegality under state law. The majority opinion held that the contract was unenforceable due to its violation of state law and thus could not be upheld by federal courts. Justice Field dissented from this decision, arguing that while it is true that contracts which are illegal under state laws cannot be enforced in federal court, there may still exist circumstances where such contracts should nevertheless receive judicial protection if they do not violate public policy or morals. In this case specifically, Justice Field argued that since neither party had any knowledge of the illegality of their agreement at the time it was made and no fraud or misrepresentation occurred during its formation, then enforcing it would not go against public policy nor morality and therefore should have been allowed to stand in court.