What are the three fundamental systems for structuring government? national, international, and transnational confederal, federal, and unitary local, regional, and global democracy, autocracy, and oligarchy?

confederal, federal, and unitary

In a confederal government system (a confederation or confederacy), states or localities are sovereign, and may delegate certain specific powers to a central government.

In a unitary government system, the central government is the seat of power and grants certain powers to state or local governments.

In a federal government system, certain powers are designated to the states and certain powers designated to the national government.  (This is the system the United States employs.)