Which principle allows courts to declare laws unconstitutional?

• A. Federalism
• B. Due process
• C. Habeas corpus
• D. Judicial review

Answer: (D)

Judicial review is the power of courts to interpret the Constitution and strike down laws or government actions that conflict with it. This creates a check on legislative and executive power by ensuring laws stay within constitutional bounds. The authority to do this was established in the early republic, most famously in Marbury v. Madison (1803), when the Supreme Court asserted that it could review acts of Congress and the president for constitutionality. Consequently, courts can declare laws unconstitutional when they violate constitutional limits. Related terms include federalism, which concerns how power is divided between national and state governments; due process, which guarantees fair treatment in legal proceedings; and habeas corpus, which protects against unlawful detention. But the specific mechanism described is judicial review.