>I think it is relevant because the question is whether taking out an enemy leader will end the problem.

I guess it depends if the leader is the movement or not. Facism didn't survive the elimation of the charismatic leaders.

>I think that it will if the "enemy" population are themselves tired and beaten after a long and costly war. However, in a country where the "enemy" population are not beaten then perhaps the killing of their leader may galvanize them even more.

Not really disagreeing with you. A long a costly war might be ingredient to defeating the morale of the population, but isn't necessary or sufficient. For instance, the war against Iraq has lasted since August 1990, some 15 years. Plus an economic blockade, yet the people, or a portion of them are fighting on.