Game Text: Your empire threatens (other empire name) with death and destruction if they don't fold themselves into your empire. (locks gentle and brutal takeover options) (Requires a fleet with sufficent power to be adjacent to threatened empire's territory.
This can be used to fix border gore. This should work almost all the time against empires that literally only have a single town. Can be used by huge and powerful empires to force smaller empires to submit.
Empires that are pacifist, isolationist, and carven are more likely to accept this offer.
Evil conquerors and crusaders are less likely to accept this offer
Cultists and villains will never accept this offer