[dragonwriter]

> Yes, but al-Qaeda existed for years as just a decentralized terrorist network, whereas the legitimacy and appeal of ISIS partially depends on their establishing a caliphate

Prior to the post-9/11 period, during which, after a brief spike, the value of al-Qaeda's brand fell, the Taliban in Afghanistan wasn't so much a government sponsor of terror as a government sponsored by al-Qaeda, and a key part of al-Qaeda's appeal and legitimacy. Success at establishing territory with a formal government of the style promoted by the ideology has been as much a part of al-Qaeda's appeal as it is for the Islamic State (and the failure of al-Qaeda central to maintain that is a big part of the reason that al-Qaeda in Iraq, with its greater success at that, broke away and became, through a number of steps, "The Islamic State".)