Marsh v. McPherson 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 person who was being held in custody by a private individual. The case arose when a man named Marsh was arrested by a private individual and held in custody without a warrant. Marsh then filed a petition for a writ of habeas corpus in a state court, seeking to be released from custody. The state court granted the writ, and the private individual appealed the decision to the Supreme Court. The Supreme Court held that the state court did not have the authority to issue the writ of habeas corpus. The Court reasoned that the writ of habeas corpus was a remedy that was available only to persons who were being held in custody by a public official, and not to persons who were being held in custody by a private individual. The Court also noted that the writ of habeas corpus was a remedy that was available only to persons who were being held in custody in violation of the law, and not to persons who were being held in custody for any other reason. The Court's decision in Marsh v. McPherson established that state courts do not have the authority to issue writs of habeas corpus to persons who are being held in custody by private individuals. The decision also established that the writ of habeas corpus is a remedy that is available only to persons who are being held in custody in violation of the law.

In Marsh v. McPherson, the Supreme Court was asked to decide whether a state court had jurisdiction over a case involving an alleged trespass on land located in another state. The majority of justices held that the state court did not have jurisdiction and dismissed the case. Justice Field dissented from this opinion, arguing that it should be up to each individual state to determine its own jurisdictional boundaries when it comes to matters such as these. He argued that states should be allowed some autonomy in deciding how far their laws extend beyond their borders and noted that if they are denied this power then there could be serious implications for interstate commerce and other activities between states. Furthermore, he suggested that allowing one party's interpretation of law would lead to unfairness since different interpretations may exist among various jurisdictions within a single country or even across countries themselves. In conclusion, Justice Field believed strongly in upholding the principle of federalism by allowing each individual state some degree of control over its own affairs without interference from outside sources like other states or foreign governments