"The insurgency increasingly is dominated by a few large groups with sophisticated communications. It no longer is a scattered, erratic, chaotic phenomenon. Groups are well organised, produce regular publications, react rapidly to political developments and appear surprisingly centralised.
There has been gradual convergence around more unified practices and discourse, and predominantly Sunni Arab identity. A year ago groups appeared divided over practices and ideology but most debates have been settled through convergence around Sunni Islamic jurisprudence and Sunni Arab grievances. For now virtually all adhere publicly to a blend of Salafism and patriotism." ICG Paper below.
"Sunni Islamic Jurisprudence?" I must admit that I did not expect that differences among the insurgents would be settled on the basis of Sharia. Iraqi Arab Muslims are overwhelmingly observant of the Hanafi law code and practise while the Kurds are mostly Shafa’i in inclination. The foreign fighters are Maliki if North African, the Saudis are Hanbali. Others can be whatver is prevalent "back home."
Does this mean much? No, because the four Mathahib (schools) recognise each other as "orthodox." The Shia live in another legal and religious "world."
The increasing religiosity and consolidation of the Sunni Arab insurgent groups is very bad news. It is predictable that if the war goes on long enough these groups will be unified under a "national" command. That is what happened in Indochina long ago and I predict that it will happen in Iraq.