Unitary systems are marked by the embodiment of all governmental authority in a single, central government.

Unitary systems are most distinguished by a central government that possesses all governmental authority. This central government directly exercises its authority over the citizenry, however, it may choose to delegate responsibility for certain policy areas or activities to regional or local governmental bodies. This delegating of governmental responsibilities is known as devolution. None of these sub-governing bodies possess policy areas which are exclusively under their control, therefore, any decisions they make may be overturned by the central government. Furthermore, they, and their delegated powers and areas of responsibility, exist only by the will of the central government. After all, in delegating political duties to regional or local governments, political power still ultimately rests with the central government. Moreover, the functions of these bodies are specified only in statutes and tend to be more administrative, than legislative in nature. Since the powers of the regional units are brought into existence through statutes passed by the central government, rather than constitutional entrenchment, they may be modified or even abolished by the same means through which they were brought into being.

The majority of modern states are unitary states. For example, France, Japan, Britain, and China subscribe to this system of organizing governmental authority. The primary benefit of this system is the clear, hierarchical authority structure which eliminates stalemates among the regional political units. Furthermore, the embodiment of supreme authority in a single, national government, encourages citizens to identify with the country as a whole, rather than expressing divided loyalties to regional authorities.