Combatants who receive backing from foreign powers cannot unilaterally stop war. The gains they militarily make on the ground are what justify their level of assistance. Since such assistance is not sustainable, insurgents are usually motivated to seize areas where there are minerals of oil deposits in order to have sources of revenue to pursue a protracted war. Iraq would be no different.
Hence the key to the achievement of cease fire and negotiation to settle disputes is the involvement of foreign patrons. Hence if the UN and US are to settle the crisis in Iraq, they must first bring Saudi Arabia, Qatar and Iran to discuss concrete proposals on how to establish a government of National Unity in Iraq. This is the starting point which should be pursued with urgency.
The lesson is clear. Political exclusion based on military might is not a recipe for a stable political environment. No one has monopoly over violence. What is important to bear in mind is that the vast majority of people in society are always hostages to combatants because of being disarmed. However, they are the greatest asset to peace and security. Once the international community comes up with a proposal that is acceptable to the people in Iraq, the combatants must endorse or risk isolation from the people. No armed combatants could seize and retain power without the complicity of the people. Once a balanced and proportionate share of power and resources are guaranteed to all groups, a peaceful settlement of s dispute becomes realisable.