Divide and Rule
It can be argued that the USA and UK want to keep the Moslem world weak and divided. It can be argued that the USA and UK want the Sunnis fighting the Shias in Iraq.
The following quotes are from "All going according to plan?" - By Sadi Baig (Asia Times - Asia's most trusted news source for the Middle East)
"The strands that emerge from either a three-state outcome (in Iraq), or an institutionalized secessionism, have very favorable outcomes from the US standpoint.
"It will serve to keep Saudi Arabia's oil-rich eastern provinces a cause of concern due to their Shi'ite majorities.
"Restive Kurds in the north will provide an ethnic beachhead that can be tapped when needed, and keep Turkey's regional ambitions in check.
"...Nuclear-armed Pakistan, and oil-rich Iran and Saudi Arabia, will experience great stress on their internal cohesion and relations with their neighbors, leading to geostrategic outcomes that can be easily manipulated to enhance US power.
"(There is) evidence that a conflict is being nursed between the Shi'ites and Sunnis...
"Arab politics will follow the dismal fate of Palestinian politics. This was done masterfully by Israel by first promoting extremist organizations such as Hamas, and after they had enveloped the support-base of the secular Palestinian leadership, push them in a cycle of violence...
"The friends of Israel within the US government and the Israeli establishment have been clamoring for a 'cauldronization' of the Middle East, and with it the wider Muslim world.
"Iraq is now quickly becoming a black hole that has the potential to suck in Egypt and Turkey on its western extremity, to the second-largest Muslim nation of Pakistan on its east." - Asia Times - Asia's most trusted news source for the Middle East