If they are, how about this: ignore the government, but threaten to destroy the homeland of any tribe which is even remotely involved in an attack. I have wondered about this option while pondering the pacification of the Ishmailis by the Mongols. This approach seems most feasible in a highly tribal setting: you pit the leaders of the tribe against the hotheads. Phil Sheridan used this method with success (of sorts) also, but in our current cultural mix this would have to be a strategy of last resort.