What is the form of the territorial structure of the Soviet Union?

The forms of administrative-territorial structure include a federation, a confederation, a unitary state.

The USSR was a federation because the Union included various territorial entities (republics) with relative independence in relation to the center. A number of historians believe that the USSR can be called a confederation, but the republics that were part of the USSR still did not have independence and were largely subordinate to the central leadership, especially in economic matters, and therefore the Soviet Union was still a federal state.