What concept allows for the review of laws by the judiciary?

Judicial review is the concept that empowers the judiciary to examine and invalidate laws and executive actions that are deemed unconstitutional. This principle is crucial in maintaining the rule of law and ensuring that all branches of government adhere to the Constitution, which serves as the supreme law of the land.

Judicial review was established in the landmark case of Marbury v. Madison in 1803, where the Supreme Court asserted its authority to review acts of Congress and determine their constitutionality. By enabling the judiciary to check legislative and executive powers, judicial review acts as a safeguard against potential government overreach, thereby promoting accountability and protecting individual rights.

The other options relate to governmental structure and the distribution of powers, but they do not directly facilitate the judiciary's role in assessing the legality of laws. Checks and balances describe the system that ensures no one branch dominates the others, federalism pertains to the division of power between national and state governments, and separation of powers delineates the responsibilities of the three branches of government. While all these concepts are interconnected in the functioning of a democratic system, it is judicial review that specifically relates to the review of laws by the judiciary.