One of the biggest questions about fighting terrorism is whether we intend to fight it on the military level or on the ideological level.
Wars have ideological components. Propaganda likely predated the written word. Undermining an enemy's morale can be a very effective means of turning the tide of battle. But in warfare, the ideology is there to further military aims, while in an ideological war the military is a tool for achieving ideological victories over the enemy.
It's a fundamental distinction that cuts deep into the question of what we are doing in places like Afghanistan.