Found a very cheesy strat...
from
Stardock Forums
...don't know if thats been posted before.
Take a sector with 1-3 shitty planets in it, then build 10+ starbases in there with nothing but cultural influence modules on them. Whenever someone declares war on you now, just give them one of the planets the next turn, and they will always make peace, and the planet will be yurs again in a handful of turns. Repeat as long as you want - you'll never need any kind of defense or pay any attention to political relations. Just "pop a planet" whenever someone declares war.
Take a sector with 1-3 shitty planets in it, then build 10+ starbases in there with nothing but cultural influence modules on them. Whenever someone declares war on you now, just give them one of the planets the next turn, and they will always make peace, and the planet will be yurs again in a handful of turns. Repeat as long as you want - you'll never need any kind of defense or pay any attention to political relations. Just "pop a planet" whenever someone declares war.