I’m not sure what the rule is DeepT, but I seemed to whither away an enemy colony by guarding the system.
I just noticed the first really dumb move by the AI. He keeps building ships that are only good at short range, but I keep fighting using the power to shields, which doesn’t seem to let his ships get into short range. He isn’t picking turtle, which seems like it would be better for him to get close. He is usually picking power to shields too.