How is ISIS not behaving as a state? Do they not call themselves a state? AQ never did that. Are they not administering law (as they define it) upon the regional population? AQ never did that. They lived apart for the rest of Afghan society and did not seek to impose their own Arab belief upon the local population. Rather, they left that to the Taliban. It was always clear, the Taliban was the state, AQ were GUESTs of the state, As guests that means no meddling. ISIS is different. They do NOT defer to the local tribal rulers. They seek to impose their OWN law. Only states do that.
What constraints, other than self-interest, do you imagine a state operates under?
What credentials are needed. It is self-evident. What I have done is a common tool for solving different problems, a coordinate transformation. For example if you are analyzing flow in a pipe it is useful to shift to cylindrical coordinates. A
similarity transform is useful for simplifying certain types of problems. Outside of mathematics this idea is sometimes called paradigm shift or framing. Basically in order to think about something you have to put into in a framework in which you can comprehend the data that the thing is generating. Otherwise all is noise and your thinking will be disordered and useless.
AQ is a cell-based subversive organization and it is useful to think about them as such. To gain insight one can look at examples for history of other subversive organizations. Such organizations want to disrupt, to sow disorder and spark opposition. Hence the aim for splashy "demonstrations". In fact peaceful actions by subversive organizations are often called "demonstrations". Violent ones are consider as terrorism (e.g. Oklahoma bombing or 911).
Now ISIS calls itself a state, while AQ never did. And ISIS acts like a state while AQ never did. To assume that ISIS is a subversive organization like AQ is sloppy thinking. Why not take them at their word and consider them as a state? States are frequently brutal evil things (e.g. Nazi Germany). Warlord-states like that established by the Great Heathen Army in England over 865-870 or William the first in 1066-71 are also brutal. Lawarence of Arabia was a scholar of medieval warfare and found the mode of understanding that comes from the study of medieval warlords useful into forging the Arabian tribes into a potent fighting force during WW I. Most of his fellow British officers could not understand the Arabs, by looking far enough back into the British past Lawrence found useful analogies.
If you adopt the frame of a medieval warlord, and then put yourself in the shoes of ISIS leaders, what would do? How do you build a state? How can you get other men to flock to your banner, as opposed to those of your enemies? Most warlords achieve this by being a giver of gold (money)? But to become a giver of money you have to take it from someone else, and that takes men, for which you need money. It's the classic bootstrap problem. What works is verything is reputation. Without reputation why should anyone join you--unless