Answer:
The principle of judicial review
Step-by-step explanation:
The U.S. courts have the power to strike down laws, statutes, and some government actions that violate the U.S. Constitution. Decided in 1803, Marbury remains the most important decision in U.S. constitutional law. The Court's landmark decision established that the U.S. Constitution is a real "law," not just a statement of political principles and ideals, and helped define the boundary between the executive and judicial branches of the constitutionally separate American form of government.