Why would either side go in guns blazing in the first place? That's what confuses me. There are some possible reasons, one of which is used in Inferno, but, at the ends of the day, the odds are pretty high that the GTVA is not going to build a Knossos to Earth just to send a War-group through, and it's also unlikely that Earth is going to resist the chance to re-establish its Empire and the resources/knowledge that would include access to.
The GTVA is mostly still in concept stage, whilst the ships work together, they are still, for the main part Terran and Vasudan ships, battlegroups and command groups, even if there is an over-arching governance that is mixed-race, in fact its very existence was put under strain by the NTF, had the Shivans not arrived, it may well have fractured under its own differences.
Earth would still be the political centre of an entire race, people on Earth know that, and so do the people in the GTVA, they aren't trying to get back purely because they need the resources, they are trying to get back because it is their home.
I don't think Earth would even want to resist rejoining the GTVA, there is no way it could get less out of it than it already has.
Edit: Oh, and regarding the discussion that is ensuing in here, think Londo and G'Kar, though I refuse to state which is which....