When courts declare a law unconstitutional, which principle is at work?

• A. Checks and balances
• B. Due process
• C. Federalism
• D. Popular sovereignty

Answer: (A)

The main idea here is the system of checks and balances that lets one branch limit another. When courts review laws and strike down those that conflict with the Constitution, they are using the judiciary to constrain the legislative branch. This ability for the courts to nullify laws keeps any one part of government from gaining unchecked power, which is the essence of checks and balances.

Due process is about ensuring fair treatment and proper procedures under the law, not about limiting legislative power through constitutional review. Federalism deals with how power is divided between national and state governments. Popular sovereignty is the idea that the people hold ultimate authority, expressed through elections and representation. The court’s power to declare laws unconstitutional is a concrete example of checks and balances in action.