From my reading it appears that the local government for each of the "more than a hundred star systems" colonized during the Second Exodus might be limited to that single system. In other words, the only government in the human sector which extends beyond the limits of a single system is the Terran Federation. "The Terran Federation is an alliance of semi-autonomous 'planetary' governments." In addition, while the Sol system assuredly contains multiple local governments, it appears that many of the others systems may also contain multiple governments.
Is this in accordance with your reading and understanding? How does this function with regard to regulation of trade? Should I think of the Terran Federation in terms of NATO or in terms of the EU?
"Each member government is wholly responsible for its internal affairs and may freely make agreements with other Federation governments. Foreign policy, defense against hostile aliens, threats to humanity, and the resolution of intergovernmental conflict are reserved matters for the Council of the Federation, which convenes in Antarctica City."
Takeyabue