"Sectarianism tends to internally fracture societies. It's extremely dangerous," says Raymond Hinnebusch. "Compare that to the way pan-Arabism was used to integrate the various Arabic speaking minorities who previously felt excluded, but if Arab identity was the common identity, it didn't matter if you were a Sunni or Shia, an Alawite or Druze, you were included in the community."

Marc Lynch speaks with Hinnebusch about international relations in the Middle East and emerging sectarianism in the region. Hinnebusch is a professor of international relations at the University of St. Andrews.

"People have many identities and sect may only be one of them. For quite a long time, people embraced Arab nationalism as an inclusive identity," says Ray Hinnebusch.

But what went wrong in the Middle East to see the rise of sectarianism we see today?

"If you got a similar situation to what we had in Iraq— namely, people in a failed state where people can't depend on the state for security so they fall back on their sectarian group, armed if possible. If you had a situation like that, then you would get the replication of the Iraqi disaster. And we have seen that— particularly in Syria and one could say in Yemen."

"You have Al Qaeda and the Islamic State taking advantage of this," Hinnebusch says, "The invasion of Iraq created this environment where Al Qaeda could regain its stature and its never looked back since then."

Looking to the future, Hinnebusch says: "I think people still have many identities, and the sectarian one is perhaps the most salient one at present. There is the risk a new generation will be brought up with only that one, but clearly there are other potential identities: Syrian, Arab, Sufi...there are many that are in competition and they could come back in a period of reconstruction and peace. That's what I hope."