Ketchum v. Buckley was a United States Supreme Court case that addressed the issue of whether a state court had the authority to issue a writ of mandamus to a state officer. The case involved a dispute between two parties, Ketchum and Buckley, over the ownership of a piece of land in the state of Ohio. Ketchum had obtained a judgment from the state court awarding him the land, but Buckley refused to comply with the judgment. Ketchum then sought a writ of mandamus from the state court, which would require Buckley to comply with the judgment. Buckley argued that the state court did not have the authority to issue such a writ. The Supreme Court ultimately held that the state court did have the authority to issue a writ of mandamus in this case. The Court reasoned that the writ of mandamus was a necessary remedy to ensure that the judgment of the state court was enforced. The Court also noted that the writ of mandamus was a common law remedy that had been used in the United States since the founding of the nation. As such, the Court concluded that the state court had the authority to issue the writ of mandamus in this case.

Justice Field delivered the dissenting opinion in Ketchum v. Buckley, arguing that the majority's decision was contrary to established law and precedent. He argued that a contract between two parties should be enforced according to its terms, regardless of whether it is deemed fair or equitable by a court. In this case, he noted that there was no evidence of fraud or misrepresentation on either side and thus the contract should have been enforced as written. Furthermore, Justice Field argued that if one party had made an error in drafting the agreement then they alone should bear responsibility for their mistake rather than having it imposed upon both parties through judicial intervention. Ultimately, he concluded that while courts may modify contracts when necessary to prevent injustice or inequity from occurring; such modifications must be based on clear legal authority which did not exist in this case and therefore could not justify overturning what had been agreed upon by both sides at the time of signing