[Andreas]

This isn't actually mentioned anywhere in-game, but I'd still like to speculate about it. What sort of government does the Galactic Terran Alliance have?

[aldo_14]

Most people, myself included, seem to favour an pyramid type elected system where each system sends a presidental-style representative to the GTVA council/government (with some form of UN style security of permament and rotational member systems).  The elected representatives would sit (not literally) on top of a fairly large number of elected planetary / regional officials within the system.

[Taristin]

Or Khonsu II runs it all. Both are good. ()

[Andreas]

Just to clear this up, I'm talking about GTA from Freespace 1, NOT GTVA from FS2.

[Kie99]

President of the Galaxy (terran)
Defence Minister
GTA leader
Fleet Leaders
Squadron Leaders
Grunts
Support Ship pilot
Commander of the Colossus

[NGTM-1R]

The Galactic Terran Alliance is just that: an alliance of Terran worlds. They've given up their control of external policy in exchange for military protection. Each individual world, or group of worlds, retains its own government and has internal autonomy, but the GTA has control when it comes to matters involving two or more member worlds.
Exact governmental mechanisms probably consist of a council to which each world/group of worlds elects, or appoints, a member. The GTA also represents the only significant Terran military force. It will protect its members, so they have no need of their own militaries.

[Andreas]

Thank you , that was exactly the sort of answer I was looking for. I thought the same. But what sort of "central government" exists back on Earth? Do countries still exist, and if not, then what would be the capital of GTA?

[Flaser]

The Sol system's weight probably comes from the huge number of people living there, however it's huge economy is a more likely reason.

Since stellar colonisation could have begun even before subspace was discovered - or nodes for another matter - the Sol system had probably the greatest space based economy in the entire GTA.

Probably Sol colonies are the Moon, Mars and mining colonies in the Jupiter and Kupier belt, since mining asteroids is a lot cheaper than hauling all the stuff into orbit.

The Moon and Mars could retain their economic power since their lower gravity and abundant rare (in Earth terms) resources still made their mining economical.

The separation of Earth must have crumbled the GTA economically and it must have been the center of the government as well, so it also crashed all existing interstellar bodies of regulation and trade.