Middle East crises and conflicts – the way ahead
Peace or Justice in the Arab World?
The roller coaster of Turkey-Russia relations
Defeating the Islamic State will be the easy part. The hard part will be securing the peace, making sure that the forces converging on Deir Ezzor don't start fighting among themselves. The stakes for Deir Ezzor could not be higher. The Iranians want an overland route to the Mediterranean. The Kurds want a buffer between Assad's forces and their territory further to the north. In some ways, the situation is like the end of World War II, when Soviet and American forces converged on Berlin.
The US has flaked out on the Kurds in the past, so it's understandable that they're worried about US withdrawal in Syria now, but in this case, the US won't be going anywhere for a while. Once ISIL is defeated, the US will need proxy forces on the ground to push back against both Assad and Russia.
[The Islamic State] is a very strong group which has a lot of sympathizers, its ideas are embedded and it has networks. It has a lot to draw on even as it loses its physical territory
[Stabilization is] difficult to do in Iraq and especially Syria because no one wants the U.S. to put lots of forces on the ground to be doing that and locals will struggle to do it well.