A unitary constitution is a system of governance where all powers are held by a central authority. In this structure, local governments may exist, but they derive their authority from the central government and can be altered or abolished by it. This means that the central government has the ultimate decision-making power over laws and policies. Countries like France and Japan operate under a unitary constitution, allowing for a streamlined decision-making process. This contrasts with a federal system, where power is divided between national and regional governments. In a unitary system, uniformity in laws and policies is often easier to maintain across the entire nation.