For some reason I like to drag 4x games out and create a balance of power. Unfortunately eventually one AI starts conquering all their neighbors and I have to go on a murderess rampage. Can anyone think of a game mechanic that would allow you to help out an underdog covertly?
Giving units to the decimated AI does not work as intended as they squander the resources you give them.
Maybe there could be a way to secretly fly the underdogs colors and attack as them if they agree to accept your help covertly. You could spend some of your espionage points on the conversion of your ships to the AI's colors.
Once converted they could attack any faction that the AI is at war with as long as the agreement is in place. Of course any planets you conquer would go to the AI you are helping out.