How might Dorne fare in a war against Tywin Lannister’s employment of chevauchée? Given Dorne’s limited farmland and water, wouldn’t they be forced to fight if every farm were burned, every castle pulled down, every field salted and every well poisoned? Say a campaign like William the Conqueror’s Harrying of the North? The Dornish seem unbeatable, but if their land were left so ruined that cannibalism arose and population levels collapsed, in a generation an invasion might be an easy thing.