Charles Gratiot, the plaintiff in error, was appealing a decision made by the United States Circuit Court for the District of Missouri. The case revolved around an 1838 contract between Gratiot and the government that allowed him to purchase land from Native Americans on behalf of the government. After purchasing this land, he submitted his bill to Congress but it was rejected due to certain irregularities with how he had conducted himself during negotiations with Native American tribes. As such, Gratiot sued for breach of contract and sought damages from Congress as compensation for his losses. The Supreme Court ultimately ruled against him because they found that since there were no specific terms outlined in their agreement regarding payment or reimbursement if something went wrong with negotiations, then neither party could be held liable under common law principles. Furthermore, they argued that any dispute over payments should have been settled through political channels rather than judicial ones given its nature as a public matter involving federal funds and policy decisions concerning Indian affairs

In the case of Charles Gratiot v. The United States, the Supreme Court was asked to decide whether a contract between two parties could be enforced when it had been made in violation of an act of Congress. In this particular case, Gratiot had entered into a contract with the government for supplies during wartime and he argued that since his performance under the contract was complete, he should receive payment from them even though they were not authorized by law to enter into such contracts at that time. The majority opinion held that because there was no legal authority for entering into such contracts, Gratiot's claim must fail and he would not be entitled to any compensation from the government. However, Justice Catron dissented on this issue arguing that if both parties have performed their obligations under a valid agreement then it should still be enforceable regardless of its illegality or lack thereof as long as neither party has acted fraudulently or deceitfully in making said agreement. He further stated that while Congress may pass laws prohibiting certain types of agreements between individuals and governments, those laws cannot retroactively invalidate existing contracts which are already legally binding upon both sides involved without due process being followed first before doing so.