You might be lacking basic understanding of tribal politics and economics then. In a tribal setting you have to neutralise the other tribe, as you do not have a standing army. Any conflict you get into, you are "conscripting" your entire male population.

In every kind of tribal conflict ever, regardless of having the moral upperhand, it was a bogstandard way of conduct. You dont have men to be stationed in enemy territory, that is the manpower that is NEEDED in the fields the second its time to sow or reap, so you dont fucking starve.

So any conflict comes around, you need to make sure that once its over, you will be left the f alone. You have to really hit it home. Maybe thats not obvious, but the clans in this context are probably not NATO or even UN members. :)