How to deal with a Lucifer? I think they quite sufficiently dealt with the first one. The only reason the GTA and PVN weren't able to take the Lucifer down much earlier was, that they didn't have the necessary knowledge sooner.
Since they now have that knowledge, any future Luficers are vulnerable as soon as they make a jump, unless they make sure the system they are jumping out of is clear.
And the UEF would even have far superiour fighters to get that job done. With a bit of planning and/or luck they might even be able to stir the Lucy into an unimportant node.
If it's still far out they might even make a little experiment and try what happens if they only blow up some of the reactors. That might leave the beams and/or shields inoperational.
I'm presenting the GTVA's point of view.
Didn't notice that, I though you were speaking of your own point of view there.
But the GTVA should know that the UEF didn't have the knowledge of the the second incursion. If they learned how bad the Shivan threat really is. The GTVA wouldn't have lost anything if they gave them some time. Since the UEF absolutely didn't expect an attack, they wouldn't even have lost the moment of surprise if they decided to attack at a later date.