Think of Earth using the US model for a divided government structure with an Executive, Legislative and Judicial Branch. Now remove the Judicial Branch from the equation because on this planet no one can really pass a final say or judgement on the overall. The closest relation to such a thing might be religion but it is too diverse to guide people from in itself, and also contains its own internal politics.

Nation states are the equivalent of the Executive Branch, with ability to take actions with their military.

Corporations, private capital entities, Institutions & Elites are closer in scope to a Legislative Branch (Congress) in that they're really making the laws, or more accurately pushing the agendas planet wide.

What this really means is that there are a lot of high level yet unaffiliated motives and agendas planet wide, and not a single one of them can exert enough influence to dominate, ever. So there's really a system of constant effort and resources being exerted and the winners are those that are not depleted at the current time to press their agendas. The most active, the most aggressive, in whatever form, actually control the planet.