So, going on the offensive seems very... expensive.
I've just started a war (with the Thoraxians, probably a bad idea). I had plenty of time to build before starting the fight, so crushing the first sector was easy enough. But now, I can't move forward. Any attempt to build in that wiped-out sector for myself gets flattened by a bunch of missile launchers in the core Thoraxian sector.
It seems like my only option to move forwards is to build more Guardposts / AntiAir / CounterMeasures than they have guns every turn until at least one of them completes and I can claim the sector - even then, I still need to build more attack buildings than the AI can destroy per turn. I can count 6 attack buildings that I can see, so at minimum cost, thats 7 guardposts (140k cr) per turn until one of them completes - and if the AI is smart enough to target the most complete site every turn, I'll never finish one anyway.
It seems like I can't move forwards, and the same result will happen if I try to flank and come in on another sector. What did I miss? Is this kind of stalemate meant to happen, to discourage too much outright fighting?