http://www.csmonitor.com/USA/Foreign-Policy/2015/0524/Islamic-State-on-the-march-What-fall-of-Ramadi-tells-us
No sooner had Ramadi fallen into the hands of the Islamic State than the drumbeat began. The Islamic State was on the doorstep of Baghdad. Iraqi forces were in disgrace, showing "no will to fight," United States Secretary of Defense Ash Carter told CNN Sunday. The loss was "terribly significant," added Sen. John McCain (R) of Arizona to MSNBC, suggesting that "we'll have to have more people on the ground…."
But a broader view suggests very little has changed. Indeed, at this point, the advance of the Islamic State appears to have less to do with the relentless expansion of a rigid and hateful ideology and more to do with the practical matter of tribal politics. In Iraq, the United States' guns, money, and influence are long gone, while civil war has left much of Syria in chaos. In this power vacuum, Sunni tribesmen have in many cases leaned toward the Sunni-led Islamic State, fearing that Baghdad and Damascus are simply stooges for Shiite Iran.
In some respects, this presents a blueprint for how to constrict the space available to the Islamic State. Seven years ago, the US military helped drive a "Sunni Awakening" that significantly undermined Al Qaeda authority in Sunni areas of Iraq. Back then, it was the "strongest power," in Mr. Abdul-Hussain's words, and acted to woo and focus Sunni tribes against the atrocities of Al Qaeda.