This case was between the plaintiff in error, Mills, and the defendants in error, The President, Directors and Company of the Bank of the United States. At issue was whether or not a state court had jurisdiction to decide on a contract dispute between two citizens from different states when it involved an act of Congress. Specifically at issue were notes issued by Mills that were payable to him but endorsed over to another party who then presented them for payment at one of the bank's branches located outside his home state. The Supreme Court held that since this transaction involved an act passed by Congress which regulated interstate commerce, only federal courts had jurisdiction over such matters and thus could hear disputes arising out of contracts involving these acts. This decision established precedent for future cases regarding federal laws governing interstate commerce as well as those concerning diversity among parties in contractual disputes.

In this case, the Supreme Court was asked to decide whether a state court had jurisdiction over an action brought by a citizen of another state against the Bank of the United States. The majority opinion held that it did not have such jurisdiction because Congress had granted exclusive authority to federal courts in matters involving citizens from different states. However, Justice Story dissented and argued that while Congress may have intended for federal courts to be given exclusive authority in certain cases, they could not do so without infringing on states’ rights under the Constitution. He further argued that if Congress wanted to grant exclusive power over these types of cases, then it should pass legislation explicitly granting such power instead of relying on implied powers or interpretations of existing laws. In conclusion, Justice Story believed that since there was no explicit law giving federal courts sole jurisdiction over interstate disputes between citizens from different states, then state courts still retained their right to hear those cases as well.