Originally Posted by
Steven L Jordan
The best way to defeat an enemy without violence is to make them believe they're better off with you than without you. How you do that is open to interpretation, but often the introduction of a mutual threat that can only be vanquished by cooperation can be enough to unite warring factions.
For an example, see "Watchmen."
Then there's the Absolute Defense model: If you have a defense the enemy can't beat, they can't defeat you.
For an example, see "The Great Wall of China."
Another tactic is to simply surrender to the enemy: Accepting the rule of a prospering society may be preferable to destruction.
For an example, see "The Mouse That Roared."