Constitution

A constitution is a document or collection of laws that forms the highest law of a state. It defines how government is structured, how power is distributed, and the limits of that power. Any law that comes below it, if it contradicts the constitution, cannot be enforced.

Most constitutions contain a preamble (for example, stating that power comes from the people), a section on fundamental rights, a section on state institutions, and a section describing how the constitution may be amended. Some are a single written and codified document, while others are scattered across laws, court rulings, and political custom.

Key functions

A constitution works in three main ways. First, it creates institutions—the legislature, executive, and judiciary—each with defined functions. Second, it divides power so that no single institution holds all authority, a principle known as separation of powers. Third, it protects individual rights and restricts the state from interfering with them.

Forms of government structure

Constitutions differ in how power is distributed between central and regional levels. In a unitary system, the greatest power lies with the central government. In a federal system, power is divided between the central government and lower governments, each with powers granted by the constitution. Constitutions also distinguish between presidential, parliamentary, and hybrid systems.

Amendment and protection

Most constitutions have amendment procedures that are more difficult than ordinary lawmaking—for example, requiring a supermajority vote in parliament or a referendum. Some provisions may be designated as unamendable. Protection of the constitution is usually enforced by a constitutional court or supreme court, which reviews whether laws and government actions comply with it.

Written and practiced constitution

There can be a significant gap between what is written in a constitution and how power is actually exercised. Political culture, the strength of courts, and the power of institutions determine how much of the written text is enforced in practice. For this reason, scholars distinguish between the formal constitution and the living constitution.