What do we call the power of the courts to declare laws unconstitutional?

Judicial review is the power of courts to examine laws and government actions and to invalidate those that are found to be in conflict with the Constitution. This principle is a fundamental aspect of the checks and balances system within the U.S. federal government, establishing the judiciary as an equal branch of government with the ability to oversee the legality of legislative and executive actions.

The concept was famously established in the landmark case of Marbury v. Madison in 1803, where the Supreme Court asserted its authority to review acts of Congress. Judicial review ensures that the Constitution remains the supreme law of the land, meaning that any law that contradicts this foundational document can be struck down, thus protecting individual rights and maintaining the rule of law.

Understanding this concept is critical for grasping how the judicial system influences and interacts with the other branches of government, ensuring accountability and adherence to constitutional principles.