Cable v. Ellis was a United States Supreme Court case that addressed the issue of whether a state court had the authority to modify a contract between two parties. The case involved a dispute between two parties, Cable and Ellis, over a contract for the sale of a tract of land. Cable had agreed to sell the land to Ellis for a certain price, but Ellis later sought to modify the contract by reducing the price. Cable argued that the state court did not have the authority to modify the contract, and that the contract should remain as originally agreed upon. The Supreme Court ultimately held that the state court did have the authority to modify the contract. The Court reasoned that the contract was not a matter of public policy, and that the parties had the right to modify the contract as they saw fit. The Court also noted that the state court had the authority to modify the contract in order to ensure that the parties were treated fairly and equitably. As such, the Court held that the state court had the authority to modify the contract between Cable and Ellis.

In Cable v. Ellis, the Supreme Court was tasked with determining whether a state court had jurisdiction to hear an appeal from a probate court's decision regarding the validity of certain deeds. The majority opinion held that the state court did not have such jurisdiction because it lacked authority over matters involving federal law and thus could not review decisions made by federal courts or agencies. Justice Field dissented, arguing that while there may be some cases in which a state court lacks authority to review decisions made by federal courts or agencies, this case is different because it involves only questions of local law and does not involve any matter of national concern. He further argued that if states are denied their right to exercise judicial power over matters within their own borders then they will become mere appendages of the Federal government instead of sovereign entities in their own right. As such, he concluded that denying states' rights would lead to an unconstitutional concentration of power in Washington D.C., something he believed should be avoided at all costs