Inter-communal violence between Sunni and Shi’a factions began to prevail after the 2003 invasion of Iraq, and gradually escalated to comprising elements of a civil war, as evaluated by the National Intelligence Estimate. Numerous attacks and counterattacks caused bloodshed, bringing up the refugee count to more than 4 million by 2008 UNHCR – Iraq: Latest return survey shows few intending to go home soon. Published 29 April 2008. Retrieved 20 May 2008., and deepened the sectarian divide.

As Sunni political participation increased during 2009 and 2010, Sunni groups active during the Insurgency declined in activity, leading sectarian relationship to a period of relative calm. However, after the withdrawal of US forces in 2011, then Prime Minister Nouri al-Maliki abandoned the non-sectarian nationalist platform that allowed for increased Sunni political representation adopted in 2009, and started to take on aggressive policies to eliminate political opponents, thus leading to the marginalization of Sunni leaders. This sparked anti-government protests in majority-Sunni Arab areas, which demanded, inter alia, de-Baathification reforms and a repeal of Article 4 anti-terrorism laws which they believe were in place to target Sunnis. The key problem is that without effective political representation, the Sunni population are left with few options to address their grievances. http://www.

understandingwar.org/report/iraqs-sunnis-crisisSectarian frustrations may fuel terrorism. A 2013 anti-government protest, which turned violent, was hijacked by terrorist groups to advocate for violent uprising. Although the majority of Sunni Arabs reject terrorism, it still possesses the potential to feed upon Sunni frustrations, while some of the Sunni population might see it as a tool to settle historical and political grievances.The threat of another Sunni insurgency still exists.

Sectarian attacks have elevated to a level not seen since 2007, and those who favor an armed uprising by Sunnis may be further emboldened by the Syrian Civil War.