Judicial review is a process under which executive and (in some countries) legislative actions are subject to review by the judiciary. A court with judicial review power may invalidate laws and decisions that are incompatible with a higher authority; an executive decision may be invalidated for being unlawful or a statute may be invalidated for violating the terms of a written constitution. Judicial review is one of the checks and balances in the separation of powers: the power of the judiciary to supervise the legislative and executive branches when the latter exceed their authority. The doctrine varies between jurisdictions, so the procedure and scope of judicial review may differ between and within countries.
Judicial review can be understood in the context of two distinct—but parallel—legal systems, civil law and common law, and also by two distinct theories of democracy regarding the manner in which government should be organized with respect to the principles and doctrines of legislative supremacy and the separation of powers.
First, two distinct legal systems, civil law and common law, have different views about judicial review. Common-law judges are seen as sources of law, capable of creating new legal principles, and also capable of rejecting legal principles that are no longer valid. In the civil-law tradition, judges are seen as those who apply the law, with no power to create (or destroy) legal principles.
Secondly, the idea of separation of powers is another theory about how a democratic society's government should be organized. In contrast to legislative supremacy, the idea of separation of powers was first introduced by Montesquieu; it was later institutionalized in the United States by the Supreme Court ruling in Marbury v. Madison under the court of John Marshall. Separation of powers is based on the idea that no branch of government should be able to exert power over any other branch without due process of law; each branch of government should have a check on the powers of the other branches of government, thus creating a regulative balance among all branches of government. The key to this idea is checks and balances. In the United States, judicial review is considered a key check on the powers of the other two branches of government by the judiciary.
Differences in organizing "democratic" societies led to different views regarding judicial review, with societies based on common law and those stressing a separation of powers being the most likely to utilize judicial review. Nevertheless, many countries whose legal systems are based on the idea of legislative supremacy have learned the possible dangers and limitations of entrusting power exclusively to the legislative branch of government. Many countries with civil-law systems have adopted a form of judicial review to stem the tyranny of the majority.
Another reason why judicial review should be understood in the context of both the development of two distinct legal systems (civil law and common law) and two theories of democracy (legislative supremacy and separation of powers) is that some countries with common-law systems do not have judicial review of primary legislation. Though a common-law system is present in the United Kingdom, the country still has a strong attachment to the idea of legislative supremacy; consequently, judges in the United Kingdom do not have the power to strike down primary legislation. However, since the United Kingdom became a member of the European Union there has been tension between its tendency toward legislative supremacy and the EU's legal system, which specifically gives the Court of Justice of the European Union the power of judicial review.
Most modern legal systems allow the courts to review administrative acts (individual decisions of a public body, such as a decision to grant a subsidy or to withdraw a residence permit). In most systems, this also includes review of secondary legislation (legally enforceable rules of general applicability adopted by administrative bodies). Some countries (notably France and Germany) have implemented a system of administrative courts which are charged with resolving disputes between members of the public and the administration. In other countries (including the United States and United Kingdom), judicial review is carried out by regular civil courts although it may be delegated to specialized panels within these courts (such as the Administrative Court within the High Court of England and Wales). The United States employs a mixed system in which some administrative decisions are reviewed by the United States district courts (which are the general trial courts), some are reviewed directly by the United States courts of appeals and others are reviewed by specialized tribunals such as the United States Court of Appeals for Veterans Claims (which, despite its name, is not technically part of the federal judicial branch). It is quite common that before a request for judicial review of an administrative act is filed with a court, certain preliminary conditions (such as a complaint to the authority itself) must be fulfilled. In most countries, the courts apply special procedures in administrative cases.
There are three broad approaches to judicial review of the constitutionality of primary legislation—that is, laws passed directly by an elected legislature.
Some countries do not permit a review of the validity of primary legislation. In the United Kingdom, statutes cannot be set aside under the doctrine of parliamentary sovereignty. Another example is the Netherlands, where the constitution expressly forbids the courts to rule on the question of constitutionality of primary legislation.
In the United States, federal and state courts (at all levels, both appellate and trial) are able to review and declare the "constitutionality", or agreement with the Constitution (or lack thereof) of legislation by a process of judicial interpretation that is relevant to any case properly within their jurisdiction. In American legal language, "judicial review" refers primarily to the adjudication of constitutionality of statutes, especially by the Supreme Court of the United States. This is commonly held to have been established in the case of Marbury v. Madison, which was argued before the Supreme Court in 1803. A similar system was also adopted in Australia.
In 1920, Czechoslovakia adopted a system of judicial review by a specialized court, the Constitutional Court as written by Hans Kelsen, a leading jurist of the time. This system was later adopted by Austria and became known as the Austrian System, also under the primary authorship of Hans Kelsen, being emulated by a number of other countries. In these systems, other courts are not competent to question the constitutionality of primary legislation; they often may, however, initiate the process of review by the Constitutional Court.
Russia adopts a mixed model since (as in the US) courts at all levels, both federal and state, are empowered to review primary legislation and declare its constitutionality; as in the Czech Republic, there is a constitutional court in charge of reviewing the constitutionality of primary legislation. The difference is that in the first case, the decision about the law′s adequacy to the Russian Constitution only binds the parties to the lawsuit; in the second, the Court's decision must be followed by judges and government officials at all levels.