Deffeback v. Hawke 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, John Deffeback, was held in a federal prison in Indiana. Deffeback sought a writ of habeas corpus from the state court, claiming that he was being held in violation of the Constitution. 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 a federal prison. 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 imprison individuals. The Court also noted that the writ of habeas corpus was a remedy that could only be used to challenge the legality of a person's detention, and not to challenge the conditions of the detention. The Court's decision in Deffeback v. Hawke 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 principle that state courts cannot interfere with the federal government's authority to imprison individuals.

In Deffeback v. Hawke, the Supreme Court was tasked with deciding whether a state court had jurisdiction to hear an appeal from a probate court in another state. The majority opinion held that it did not have such jurisdiction and affirmed the decision of the lower courts. Justice Field dissented, arguing that under principles of comity between states, each should respect judgments rendered by other states' courts unless there is clear evidence that those judgments were obtained through fraud or collusion. He argued further that since no such evidence existed in this case, then it would be unjust for one state's court to refuse to recognize decisions made by another's court on matters within its own jurisdiction. In conclusion, he maintained that if two states are equally competent and independent authorities over certain matters within their respective jurisdictions then they should both be allowed equal recognition when rendering judgment on those same matters without interference from either side