Does the UEF even have a tenable long-term aim, militarily? I understand that most of the UEF leadership is pushing solely for diplomatic resolutions, but for those hardliners, like Calder, do they really have an actual objective? They cant win. They GTVA has installed a Backdoor to the Sol system, Kicked it in, and theres no way for Sol to get rid of it, short of collapsing it again. They cant invade, they cant hold it, as the Tevs wouldn't give them time to entrench (and they can just fry close blockades with Area-Denial Meson weapons, as was stated above,) and if they back off to allow for not being simply annihilated, as soon as the GTVA wants back in, then they have the room they need to simply disperse back into the system again, even if the UEF does somehow drive them out in the first place.
I cant help but feel that for all their tenacity, the minds behind the Wargods don't really have any sort of actual plan, beyond hoping that the folks back home in the Tev systems get sick of the war. That seems like a flimsy thing to base your entire strategy off of.