Consitiutions of the High Frontier

How do you the settlements in space would be organized? I think there
would a central government for each high planetary orbit. It would
confederal than federal, more like the UN, the EU or Swizerland, than
Australia, Canada or the USA. It would mainly be a milatary-economic
organization to defend the settlement from attacks from Earth or a
colonized Mars/Venus/other planets and to premote trade and commerce
among its members. It would layout where settlements would orbit, and
build new settlements as well.

Since the settlements are not physical connected, the central
govenment could not become overpower indivdual settlement government.
They would regulate the internal politics of the settlement.