Finally, most states have a supreme court. This is the most powerful court in the state. If a person has already appealed to the appellate courts, and they still think the court's decision was wrong, they can appeal to the state supreme court. Once the state supreme court makes a decision, that decision becomes state law. The decision can only be changed or reversed by federal courts. That can only happen if the federal courts think the state supreme court made a decision that violated the Constitution.