For the US it is essential the role of Sunni tribes against the caliphate

The loss of the city of Ramadi, conquered by the Islamic state, marked a defeat for the regular Iraqi forces and the US strategy in the fight against the forces of the caliphate. Washington has not insisted enough in and involvement in the preparation of the Sunni tribal forces, identified as a factor to be deployed alongside Iraqi army, in order to keep the conflict in the area, within the matrix Sunni. While realizing that the combat capability of the Shiite militias is higher, the White House prefers still try to maintain, in some areas of Iraq, clashes between fighters, albeit conflicting, with the same religious affiliation. One of the main reasons is to not alienate the support of Sunni tribes opposed to the Caliphate, considered essential for the reconquest of the territories invaded by the Iraqi Islamic state, especially in the light of a final defeat of the caliphate. In fact, if the Shiite militias may be right more easily than fundamentalist Sunnis, the victory is short-term, because it allows Shiites to increase its influence and generate discontent of the Sunnis, who becomes bound to result in the formation of new militias, which in the future they would be in opposition to the Shiites. The new US strategy, however, points to win in a lasting way, through the military defeat of the Islamic state, which must follow a stabilization policy can maintain balance, allowing the majority of the Sunni population to administer, without other interference. This strategy also serves to demonstrate to the US allies of the Gulf monarchies and generally moderate Sunni states, that Washington does not intend to endorse the increasing territorial influence, that Iran is trying to impose on several Iraqi areas, mostly Sunni through its military capacity. This vision may involve a scenario of reorganization for Iraq, if not with the division of the state, at least with the adoption of a federal form of government, where the Sunnis are divided by Shiites. Since the fall of Saddam Hussein's Iraq is ruled by a minority Shiite and Sunnis are poorly involved in political decisions, this is something that has greatly favored the initial adherence to the Islamic state and its expansion. Only after the 'exercise of power and too violent fundamentalist Islamic state, different tribal groups rebelled against the Caliphate and have become part of the coalition that has been joined to the regular Iraqi forces. The most urgent is, at present, to achieve military victories can make back the troops of the Islamic state, but to get through the Sunni tribal forces. To this end the US has come up with more support on the ground, through a special training by US personnel, the provision of improved weapons and greater air cover. The model designed by Washington expects, therefore, the strengthening of Iraqi Sunni component contrary to the caliphate, so you can count on a loyal ally; in this regard, it was also thought to the establishment of a National Guard made up of Sunnis, but the project was rejected by the Shiite lawmakers, who feared that the creation of a paramilitary Sunni, could be too powerful a tool in the hands of the secessionists. The government in Baghdad, in the hands of the Shiites want to send Shiite militias, probably mainly coming from Iran, in Sunni areas at risk of falling into the hands of the caliphate, but the United States were opposed, as they fear a drift sectarian the conflict, as well as losing the support of the Sunni tribes. Never before has the case of conflict between Shiites and Sunnis become central to the resolution of the struggle against the Caliphate and for the balance of the region. The most feasible solution, at least for the Iraqi territory, seems to be to strictly divide the spheres of influence between Shiites and Sunnis, allied to the US, to prevent internal conflicts in the coalition against the caliphate, which would only encourage the expansion of Islamic state. The official position of the White House is one of opposition to a division of the state of Iraq, however, with ongoing international developments, a change of address of the US administration could also encourage greater international detente, about the discontent of the Gulf monarchies, and insert, in a possible process of revision of the Iraqi, even the long-standing Kurdish problem, so as to encourage the emergence of an independent state in all respects a sovereign entity of Kurdistan, starting from that of Iraq.