38. the answer is...

the Supreme Court

The U.S. Supreme Court has complete authority over all federal courts. Its rulings have a significant effect. A Supreme Court ruling can affect the outcome of many cases in the lower courts. The Supreme Court’s interpretations of federal laws and of the Constitution are final. The Supreme Court is limited in its power over the states. It cannot make decisions about state law or state constitutions. The Court can decide that a state law or action conflicts with federal law or with the U.S. Constitution. If this happens, the state law becomes invalid. The Supreme Court case ruling Marbury v. Madison established this power, known as “judicial review.” The Supreme Court also rules on cases about significant social and public policy issues that affect all Americans. The Supreme Court ruled on the court case Brown v. the Board of Education of Topeka, which ended racial segregation in schools.