Allen v. Killinger 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, John Killinger, was held in a federal prison in Ohio. Killinger sought a writ of habeas corpus from the Ohio state court, claiming that he was being held in violation of the Constitution. The federal government argued that the state court did not have the authority to issue the writ, as the federal government had exclusive jurisdiction over federal prisons. The Supreme Court ultimately held that the state court did not have the authority to issue the writ of habeas corpus. The Court reasoned that the federal government had exclusive jurisdiction over federal prisons, and that the state court did not have the authority to interfere with the federal government's authority. The Court also noted that the writ of habeas corpus was a remedy for violations of the Constitution, and that the state court did not have the authority to determine whether the federal government had violated the Constitution. As such, the Court held that the state court did not have the authority to issue the writ of habeas corpus.

In Allen v. Killinger, the Supreme Court was asked to decide whether a contract between two parties could be enforced despite one of them having died before it was completed. The majority opinion held that the contract could not be enforced because it had not been fully performed by both parties prior to the death of one party. However, in his dissenting opinion Justice Field argued that contracts should still be enforceable even if only partially performed at the time of death as long as there is evidence that both parties intended for their agreement to become binding upon completion and performance by each side. He reasoned that this would encourage people to enter into agreements with confidence knowing they will receive what they bargained for regardless of unforeseen circumstances such as an untimely death or other events beyond their control which may prevent full performance from occurring prior to either party's demise.