Kearney v. Denn was a United States Supreme Court case that addressed 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, Kearney, was held in a federal prison in the state of Pennsylvania. Kearney 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 that the state court had no authority to determine the legality of a federal prisoner's detention. 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 remedy, and that the state court did not have the power to interfere with the federal government's authority to imprison individuals.

In the case of Kearney v. Denn, the Supreme Court was asked to decide whether a contract between two parties that had been made in New York and then transferred to Pennsylvania could be enforced under Pennsylvania law. The majority opinion held that it could not, as there was no evidence that either party intended for the contract to be governed by Pennsylvania law when they entered into it. However, Justice Field dissented from this decision on several grounds. He argued that since both parties were citizens of different states at the time of entering into their agreement, they should have reasonably expected any dispute arising out of their contract would be decided according to the laws applicable in each state respectively; thus making it reasonable for them to assume their agreement would also fall within those same laws if transferred across state lines. Furthermore, he noted that even though neither party explicitly stated which jurisdiction's laws applied when signing their agreement - or later transferring it - such an intention can still be inferred based on other facts surrounding its formation and transferral; including where each party resided at those times and what type of business activities were being conducted therein. As such, Justice Field concluded his dissent by arguing against a strict interpretation of contracts formed across multiple jurisdictions without explicit language stating otherwise; instead advocating for greater consideration given towards all relevant circumstances before determining enforceability under one particular set of legal rules over another