This section traces the broad evolution of the Iraq war against Islamic State between 2013 and 2017 by identifying its main conflict episodes and by tracking key conflict factors across different periods of the civil war. These periods are connected, but also featured their own dynamics. Each had a significant impact on the next. In comparison with the Syrian civil war, the Iraqi conflict is more straightforward. It featured less complexity in terms of its degree of internationalisation, the number of nested conflicts and the fragmentation of the ‘opposition’ (IS). A key difference lies in the fact that the Iraqi state was opposed by a single radical extremist group committing gruesome acts of violence based on its eschatological world view, rather than by a range of armed rebel groups covering the ideological spectrum, as was the case in Syria. A key similarity with Syria, however, is that both wars arose in large part in response to the authoritarian practices of the state.

The emergence of Islamic State: Exploiting new social fractures

The Iraqi civil war was an armed conflict pitting a variety of Iraqi and international forces against IS from December 2013 to December 2017. Already in 2013 the IS insurgency had escalated into a full-scale war as the group launched its 12-month campaign ‘Soldiers’ Harvest’ that targeted in particular Iraqi forces in the northwest, resulting in the later conquest of Ramadi, Fallujah, Tikrit, Mosul and major parts of northern Iraq. The campaign included an attack in July 2013 on the Abu Ghraib and Taji prisons, which freed between 500 and 1,000 inmates, including senior al-Qaeda leaders and other militants. In June 2014, IS leader Abu Bakr al-Baghdadi declared the creation of an Islamic State in Mosul, Iraq’s second largest city, and named himself caliph. At its height, IS held 56,000 square kilometers - a third of Iraq’s territory and inhabited by 4.5 million of its residents. The organisation instituted a reign of terror that included rape, abductions, executions, mass murder, pillaging, extortion, seizure of state resources and smuggling.

Before the capture of Mosul by IS in 2014, international and Iraqi policy makers believed that the Islamic State of Iraq (a predecessor of IS)[56] had been defeated and another insurgency highly unlikely. They were wrong. This was mostly due to their perception of the insurgency as a disease inflicted upon society by external sources that could be rooted out, rather than viewing it as a violent manifestation of deeper social grievances. The emergence of IS was, in fact, the result of many dynamics that interacted over a long period, including the collapse of Iraqi state institutions, foreign occupation mobilising armed resistance and a civil war that tore through Iraq’s social fabric and hardened group identities. Often interpreted solely through the lens of religious doctrine and religious extremism, IS legitimacy and attraction rested on multiple trends that have been evolving deeper down within Iraqi society.

For example, IS monopolised the Sunni rebellion that emerged in 2013–2014 against al-Maliki's repressive central government in Baghdad.[57] By early 2013, tens of thousands of Sunnis were participating in anti-government protests in Ramadi, Fallujah, Samarra, Mosul and Kirkuk. Not unlike the 2019 protests, they faced a bloody crackdown.[58] While the politics of Sunni and Kurdish marginalisation played a role at the national level, intra-communal fractures (e.g. the disconnection between Sunni political elites and their constituencies) were essential in providing social inroads for IS, helping to anchor it locally, and expanding rapidly. These fractures were brought about by the major shifts in power and the emergence of new stakeholders that followed the fall of the Ba’ath regime after 2003. A good example is the demise of the ‘Awakening’, a movement of Sunni tribes that was instrumental in the fight against al-Qaeda in Iraq between 2006 and 2008. Its dismantlement by Prime Minister al-Maliki can be seen as both a cause and a consequence of the marginalisation and fragmentation of Iraq’s Sunni community after the fall of Saddam Hussein. As a result of the Awakening’s disempowerment at the hands of the Shi’a-dominated Iraqi state, many of its remnant groups fell victim to / joined the extremist forerunners of IS.[59]

Internal displacement and the proliferation of informal settlements in response to war and violence added new socio-political cleavages that split traditional social structures and disrupted community authority. By promising a new era of Sunni dominance, IS drew widespread support from disenfranchised Sunnis and was able to expand its territories rapidly. Depending on the context, IS served as a form of empowerment, not only against the government and its repression, but also as a mechanism to address local grievances, i.e. to carry out revenge and to settle longstanding scores that had accumulated within Sunni communities.

Key conflict episodes

Despite the gradual growth of IS between 2010 and 2014, it only erupted into international and domestic consciousness in June 2014 when its fighters first captured Mosul and then marched on to reach the outskirts of Baghdad and Erbil. In a short time, the fight against IS came to involve the Iraqi armed forces, the Popular Mobilisation Forces (PMF),[60] various Kurdish forces, several self-defence groups and tribal factions. Iran was the first foreign country to provide military assistance, partly because Sunni jihadis came within 25 miles of its border. US airstrikes against IS began in August 2014 but were initially restricted to Sinjar. In September 2014, the US formed ‘The Global Coalition to Defeat ISIS’, consisting of 79 countries and institutions. However, the coalition’s airstrike campaign and ground combat operations ‘Operation Inherent Resolve’ only began to engage seriously in 2015, supporting the recapture of Tikrit in April, Ramadi in December, Fallujah in June 2016 and Mosul in July 2017.

Looking back from a conflict prevention perspective, the full-blown emergence of IS could have been foreseen prior to its dramatic seizure of Mosul, which brought in cash, recruits and weapons in large quantities. In late 2013/early 2014, IS was already on the rise before it morphed from a shadowy insurgent network into a quasi-state that held territory, collected taxes and conducted large-scale military operations.[61] The Iraqi government did in fact request international (US) assistance, but the Obama administration declined to intervene militarily – acting only after Mosul had fallen and IS had taken control of a third of the country, with both Baghdad and Erbil under threat.[62] Allowing IS to consolidate control of Mosul and much of Anbar dramatically raised the costs and duration of the military campaign needed to defeat it. What transpired was devastating urban warfare in mostly Sunni-dominated cities, thus, in a sense, aggravating the original problem. The US military used 29,000 munitions in the form of bombs, rockets and artillery during the campaign to liberate Mosul alone, decimating basic infrastructure. The capital city of Anbar province, Ramadi, was reported to have been 80 per cent destroyed by the 2015 liberation campaign – a fate not dissimilar to that of Raqqa in neighbouring Syria. Moreover, had IS not taken Mosul and threatened Baghdad, the Iraqi government would not have become as dependent on the mobilisation of an array of armed groups, often supported by sectarian and regional actors, that helped prevent the outright collapse of the state but went on to subtly undermine it afterwards.

Ever since IS lost its last stronghold in 2017, security experts have warned about the risk of resurgence. The only reliable way to reduce this risk is to address reconciliation and grievances with and within Iraq’s Sunni community, which is not happening at present. In fact, the opposite seems to be the case as an initial popular campaign of revenge has been followed by a government policy of further neglect.[63] The preceding analysis has highlighted a few further issues for consideration: