Constitutionality

Constitutionality is the condition of acting in accordance with an applicable constitution; the status of a law, a procedure, or an act's accordance with the laws or guidelines set forth in the applicable constitution. When one of these (laws, procedures, or acts) directly violates the constitution, it is unconstitutional. All the rest are considered constitutional until challenged and declared otherwise.

An act (or statute) enacted as law either by a national legislature or by the legislature of a subordinate level of government (such as a state or province) may be declared unconstitutional.

However, governments do not just create laws. Governments also enforce the laws set forth in the document defining the government—in the Constitution. In the United States, the failure to seat duly elected representatives of the people following a proper election, or the failure to provide for such elections would be unconstitutional even in the absence of any legislated laws whatsoever.

When the proper court determines that a legislative act (a law) conflicts with the constitution, it finds that law unconstitutional and declares it void in whole or in part. This is called judicial review. The portion of the law declared void is considered struck down, or the entire statute is considered struck from the statute books.

Depending on the type of legal system, a statute may be declared unconstitutional by any court, or only by special Constitutional courts with authority to rule on the validity of a statute. In some countries, the legislature may create any law for any purpose, and there is no provision for courts to declare a law unconstitutional. This can occur either because the country has no codified constitution that laws must conform to (e.g., the United Kingdom and New Zealand) or because the constitution is codified but no court has the authority to strike down laws on the basis of it (e.g., the Netherlands and Switzerland).

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