A constitution is the aggregate of fundamental principles or established precedents that constitute the legal basis of a polity, organization or other type of entity, and commonly determines how that entity is to be governed.
When these principles are written down into a single document or set of legal documents, those documents may be said to embody a written constitution; if they are encompassed in a single comprehensive document, it is said to embody a codified constitution. The Constitution of the United Kingdom is a notable example of an uncodified constitution; it is instead written in numerous fundamental Acts of a legislature, court cases, or treaties.
Constitutions concern different levels of organizations, from sovereign countries to companies and unincorporated associations. A treaty that establishes an international organization is also its constitution, in that it would define how that organization is constituted. Within states, a constitution defines the principles upon which the state is based, the procedure in which laws are made and by whom. Some constitutions, especially codified constitutions, also act as limiters of state power, by establishing lines which a state's rulers cannot cross, such as fundamental rights.
The Constitution of India is the longest written constitution of any country in the world, with 146,385 words in its English-language version, while the Constitution of Monaco is the shortest written constitution with 3,814 words. The Constitution of San Marino might be the world's oldest active written constitution, since some of its core documents have been in operation since 1600, while the Constitution of the United States is the oldest active codified constitution. The historical life expectancy of a constitution since 1789 is approximately 19 years.
Etymology
The term constitution comes through French from the Latin word , used for regulations and orders, such as the imperial enactments (constitutiones principis: edicta, mandata, decreta, rescripta). Later, the term was widely used in canon law for an important determination, especially a decree issued by the Pope, now referred to as an apostolic constitution.
William Blackstone used the term for significant and egregious violations of public trust, of a nature and extent that the transgression would justify a revolutionary response. The term as used by Blackstone was not for a legal text, nor did he intend to include the later American concept of judicial review: "for that were to set the judicial power above that of the legislature, which would be subversive of all government".
General features
Generally, every modern written constitution confers specific powers on an organization or institutional entity, established upon the primary condition that it abides by the constitution's limitations. According to Scott Gordon, a political organization is constitutional to the extent that it "contain[s] institutionalized mechanisms of power control for the protection of the interests and liberties of the citizenry, including those that may be in the minority".
Activities of officials within an organization or polity that fall within the constitutional or statutory authority of those officials are termed "within power" (or, in Latin, intra vires); if they do not, they are termed "beyond power" (or, in Latin, ultra vires). For example, a students' union may be prohibited as an organization from engaging in activities not concerning students; if the union becomes involved in non-student activities, these activities are considered to be ultra vires of the union's charter, and nobody would be compelled by the charter to follow them. An example from the constitutional law of sovereign states would be a provincial parliament in a federal state trying to legislate in an area that the constitution allocates exclusively to the federal parliament, such as ratifying a treaty. Action that appears to be beyond power may be judicially reviewed and, if found to be beyond power, must cease. Legislation that is found to be beyond power will be "invalid" and of no force; this applies to primary legislation, requiring constitutional authorization, and secondary legislation, ordinarily requiring statutory authorization. In this context, "within power", intra vires, "authorized" and "valid" have the same meaning; as do "beyond power", ultra vires, "not authorized" and "invalid".