Focus on the populace, not the leaders. No matter how extreme the opposing leaders may be, you are still competing for the support of your own populace, and that is family. Sometimes certain members just need to be divorced or excommunicated. But it's still family.

Or, just apply CvC and treat insurgency like war and use the military to kill enough of the populace to gain their obedience and support. This is the COA most often applied by governments, and I just don't see that it ever produces more than a temporary lull in the fighting, and a temporary extention of their flawed reign of power.

I realize I may be totally F'd up on this, but I don't think that I am and am open to good arguments and historical examples; recognizing that all historical examples must be tailored for the modern information age of today that renders many TTPs used to "separate the insurgent from the populace" largely obsolete. Greater burden today for governments to actually govern, this is the price of an empowered populace.