In some countries, courts not only interpret legislation but also determine its validity (constitutionality), and in so doing they sometimes nullify statutes passed by legislatures. A court empowered with such authority may declare that a piece of legislation is null and void because it is incompatible with constitutional principles (e.g., some restrictions on the right to have an abortion in the United States have been found by the U.S. Supreme Court to be incompatible with the right to personal privacy—itself a contested constitutional principle that was developed by the court beginning only in the 1960s). This happens only in countries that have written constitutions and that have developed a doctrine of “judicial supremacy” (in contrast to “parliamentary supremacy,” which is generally found in countries following the model of the United Kingdom). When scholars speak of “limited government,” they mean specifically that the policy options available to governments are constrained by constitutional principles that are enforced by an independent judiciary. The prime example is the United States, and the classic statement of the doctrine is the Supreme Court’s decision in Marbury v. Madison (1803), in which Chief Justice John Marshall said:

The powers of the legislature are defined and limited; and [so] that those limits may not be mistaken, or forgotten, the Constitution is written. To what purpose are powers limited, and to what purpose is that limitation committed to writing, if these limits may, at any time, be passed by those intended to be restrained? The distinction between a government with limited and unlimited powers, is abolished, if those limits do not confine the persons on whom they are imposed, and if acts prohibited and acts allowed, are of equal obligation. It is a proposition too plain to be contested, that the Constitution controls any legislative act repugnant to it.…It is emphatically the province and duty of the judicial department to say what the law is. Those who apply the rule to particular cases, must of necessity expound and interpret that rule. If two laws conflict with each other, the courts must decide on the operation of each.

Armed with this powerful precedent from this very early date in the development of the U.S. legal system, the Supreme Court of the United States has held many statutes—federal as well as state—unconstitutional and has also invalidated executive actions that it believed violated the Constitution.

Perhaps even more surprising is the fact that all lower courts in the United States also possess and exercise the same powers as the Supreme Court. Whenever a question arises in any U.S. court at any level as to the constitutionality of a statute or executive action, that court is obligated to determine its validity in the course of deciding the case before it. Indeed, the case may have been brought for the sole and express purpose of testing the constitutionality of the statute (e.g., a law requiring racial segregation or restricting freedom of speech), or it may be an ordinary civil or criminal case in which a constitutional question incidental to the main purpose of the proceeding is raised (e.g., the legality of a search and seizure by the authorities). Every judge in the United States is legally empowered to engage in constitutional interpretation. When a lower court decides a constitutional question, however, its decision is subject to appellate review, sometimes at more than one level. When a state statute is challenged as violating the state constitution, the final authority is the supreme court of that state; when a federal or state statute or a state constitutional provision is challenged as violating the Constitution of the United States, the ultimate arbiter is the U.S. Supreme Court.

In a few U.S. states and in many countries, questions as to the constitutional validity of a statute may be referred in abstract form to a high court by the chief executive or the legislature for an advisory opinion. In most systems, however, this is unusual and, in any event, supplementary to the normal procedure of raising and deciding constitutional questions. The normal pattern is for a constitutional question to be raised at the trial-court level in the context of a genuine controversy and decided finally on appellate review of the trial-court decision.

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The U.S. pattern of constitutional adjudication is not followed in all countries that have written constitutions. In some countries (e.g., Germany), there is a special court at the highest level of government that handles only constitutional questions and to which all such questions are referred as soon as they arise and before any concrete controversy occurs. A constitutional question may be referred to the special court in abstract form for a declaratory opinion by a procedure similar to that prevailing in the minority of U.S. states that allow advisory opinions. In France, members of the parliament may demand (and increasingly have demanded) that the constitutionality of legislation be certified by the Constitutional Council prior to its becoming law.

In other countries, written constitutions may be in effect but not accompanied by any conception that their authoritative interpretation is a judicial function. Legislative and executive bodies, rather than courts, act as the guardians and interpreters of the constitution, being guided by their provisions but not bound by them in any realistic sense. Modernization in the developing countries (as in Latin America, Asia, and sub-Saharan Africa) and the transformations from authoritarian to democratic governance (e.g., in Greece, Portugal, and Spain in the 1970s and ’80s) have meant that there are fewer instances of wholly impotent courts. Still, in some countries, the courts remain captive to political elites or open to manipulation by the government, or the courts’ authority to exercise the judicial review to which they are constitutionally entitled remains tenuous. In 1993, for example, the Russian constitutional court was dissolved by Pres. Boris Yeltsin and replaced with a system of appointments that ensured greater presidential control.

Finally, some countries, such as the United Kingdom, have no formal written constitution. In such countries, parliamentary supremacy clearly prevails, though European law (i.e., the law of the European Union [EU]) now supersedes parliamentary supremacy in all EU countries, including the United Kingdom. The courts have no power to invalidate statutes, though they can and do interpret them, which is a very important judicial power.