Butt v. Ellett was a United States Supreme Court case that dealt with the issue of whether a state court had the authority to issue a writ of error to a federal court. The case arose when the plaintiff, Butt, sued the defendant, Ellett, in a state court in Mississippi. Ellett then filed a writ of error in the federal court, claiming that the state court did not have jurisdiction over the case. The Supreme Court held that the state court did not have the authority to issue a writ of error to a federal court. The Court reasoned that the state court was not a court of competent jurisdiction to issue a writ of error to a federal court, and that the writ of error was therefore invalid. The Court also held that the state court had no authority to review the decision of the federal court. The Court concluded that the writ of error was void and that the state court had no authority to review the decision of the federal court.

In Butt v. Ellett, the Supreme Court was asked to decide whether a state court had jurisdiction over an action brought by citizens of one state against citizens of another in which the amount in controversy exceeded $500. The majority opinion held that it did not have such jurisdiction and reversed the judgment below. Justice Field dissented from this decision, arguing that under Article III Section 2 Clause 1 of the Constitution, Congress has given federal courts exclusive original jurisdiction over cases between two or more states when there is diversity of citizenship and an amount in controversy exceeding $500. He further argued that since no other court has been established with concurrent power to hear these types of cases, then any attempt by a state court to exercise such authority would be unconstitutional as it would violate both Article III and Amendment XI's prohibition on suits being brought against a State without its consent.