There have been a number of frantic headlines in the past couple days reporting things likes “Extremist Group Takes Syrian Towns, Key Oil Field”. The suggestion is that more dominoes are falling and key leaders/communities are pledging themselves sincerely to ISIS rule.
Reading between the lines and below the lede, I suspect that the story there is less some dramatic conquest by ISIS and more of another ephemeral mass defection of the neo-feudal eastern Syrian “oil sheiks” — a very loose group of local warlords who have been using the civil war to make their surrounding territories into independent fiefdoms producing oil, gas, and power for all sides willing to pay. That’s a very tenuous alliance for ISIS, because these sheiks have switched sides constantly during the war. In some cases, some were producing and selling gas and power to both the Qaeda-backed Nusra Front and the government at the same time. As I explained it about a year ago:
The pre-Socialism clan system is re-asserting itself in the midst of the chaos because people need local order and income. These clan administrators take control of local oil & gas production and then essentially pay electricity or gas tributes to both the regime and the Islamist rebels to keep them off their backs.
I’m betting they defect back the moment they see an opportunity. At the moment, ISIS has access to a lot of heavy weaponry stolen in Iraq. It’s exactly the kind of stuff these warlords have previous expressed interest in acquiring through their oil and gas bartering.