Actually the shiites and kurds were able to come to agreement and compromise on their differences. It's the Sunni who have been intransigent and uncompromising. They sat out the last election and thus have no vested interest in seeing this interim government succeed in writing the constitution. That won't be the case if the constitution is voted down in Oct and a new government is elected in December.

The one positive I can see is that the Sunni will be working extremely hard to get their vote out in these two upcoming votes. That might dampen the insurgency and will put them in direct conflict with their foreign terrorist allies who want to murder anyone who votes.