Post v. Pearson 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, William Post, was held in a federal prison in New York. Post sought a writ of habeas corpus from the New York state court, claiming that he was being held in violation of his constitutional rights. 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 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 constitutional rights, and that the state court did not have the authority to determine whether Post's constitutional rights had been violated. As such, the Court held that the state court did not have the authority to issue the writ of habeas corpus.

Justice Field delivered the dissenting opinion in Post v. Pearson, arguing that the majority's decision was contrary to both precedent and reason. He argued that under prior decisions of the Supreme Court, a party who had been wrongfully dispossessed of land could not be required to pay rent for its use during such wrongful possession; rather, they were entitled to recover damages from those responsible for their loss. In this case, he argued that it was clear from the facts presented by both parties that Pearson had wrongfully taken possession of Post's property and thus should have been liable for damages instead of being allowed to collect rent as if his possession were lawful. Furthermore, Justice Field noted that allowing Pearson to retain any benefit derived from his wrongful act would set an undesirable precedent which could lead other individuals or entities with similar intentions into believing they too can take advantage of others without consequence.