It's true - if you're playing as the Federation, FORGET about capturing systems!
If you want to take an enemy system, your best chance is to wipe out the existing inhabitants, and then colonise it yourself.
If you attack the system with a massive fleet (And I do mean massive) you might be able to wipe it out in one go. This will still cause you an Empire-wide morale decrease, but this can be reduced or even negated by colonising the system.
If you have a system that is rebellious or defiant, forget about building stuff, just use martial law.
When the martial law has completed, focus on building (And powering) buildings that can increase morale. Winning a battle is also a good way of increasing your morale throughout your Empire, as well as building things like the Federation Council, since both these methods give Empire-wide morale bonuses.
If you still want to capture enemy systems, but not suffer morale problems, I could email you a modded morale file, but some people would consider that cheating or defeatist. Send me a PM or an email if you want me to send it to you.
Grimmedbythereapernew@yahoo.co.uk
It's your choice either way.
If you'd rather mod the game yourself, just go here:
Download the tool called BoTFME - that's the program that allows you to mod the morales of each of the major Empires.
You have to be logged into the site before you can download stuff though - just use the same login details that you use on this site, since armadafleetcommand is the parent site of this one.
