Judicial Structures and Judicial Review

Judicial review matters because it decides who has the last word when a law conflicts with a constitution. If courts can strike down legislation, the legislature is not supreme, the constitution is. That gives citizens a place to challenge a law after it passes, and it gives courts leverage over elected branches. Where courts lack this power, a legislature's word is close to final once it votes, no matter what a constitution says.

Mechanically, judicial review works through a case: someone challenges a law as unconstitutional, the case climbs toward the highest or a specialized constitutional court, and that court rules the law invalid and unenforceable. The law stays on the books in form but has no legal effect. This depends on a written, supreme constitution that sits above ordinary statutes, and on courts being independent enough to rule against the government that appointed them.

The United Kingdom breaks this pattern because of parliamentary sovereignty: Parliament's acts are the highest law, and no court sits above it. The UK Supreme Court can interpret statutes, apply the Human Rights Act, and tell Parliament a law seems incompatible with rights, but it cannot void the act itself; Parliament must choose to amend it. This sits next to China, where courts are formally separate but operate under the Communist Party's ultimate authority, so judicial review in the Western sense barely functions, and next to Mexico, whose Supreme Court holds full power to nullify unconstitutional laws, closer to the strong judicial review model.