Using hit-and-run tactics, the Islamic State in Iraq and the Levant, also known as ISIL, has sought to keep Iraqi security forces dispersed and under pressure. ISIL has achieved this by striking at areas where security forces are weak and withdrawing from areas where Baghdad has concentrated its combat power. The jihadists have been working hard to improve their tradecraft by developing skill sets ranging from staging complex ambushes to using Iraqi army equipment effectively in surprise raids. ISIL has also sought to better develop its ties with local Sunni communities.

As far back as the days of al Qaeda in Iraq and its predecessor, Jamaat al-Tawhid and Jihad, founded by Abu Musab al-Zarqawi, militancy has had a presence in Anbar province — and indeed in Mosul. During the Iraq War, the U.S. military considered Mosul one of the key gateways for foreign al Qaeda in Iraq fighters to enter the country. ISIL operations in Mosul and the wider Nineveh province are unsurprising. What is surprising is the degree of success that ISIL has managed to achieve in its latest offensive in the region.

This success undoubtedly has much to do with local forces and tribes who have either facilitated ISIL or elected not to fight the group's incursion into Mosul. In a city of almost 2 million, had ISIL received no local sympathy, it would have been unable to rout the Iraqi forces in the area with only 1,000 to 2,000 fighters. Social media contains several reports of local Sunnis welcoming ISIL forces, and even of local fighters supporting ISIL in attacks against government positions.

Furthermore, Iraqi security forces reportedly had around 10,000 personnel in and around Mosul. Despite the ferociousness of the ISIL attack, the fact that a significant portion of these forces fled — abandoning their uniforms, equipment and vehicles — indicates serious structural and morale issues within the force, which could be attributed in part to a high number of Sunni soldiers in the ranks who are unwilling to stand up to ISIL for Iraqi Prime Minister Nouri al-Maliki.

Having succeeded in its Mosul operations, ISIL will continue to take advantage of its momentum and push its gains at a time when the Iraqi government is scrambling to recover from significant losses. As well as taking large portions of the city, ISIL militants seized many weapons and military vehicles as well as the contents of Mosul's central bank. They also freed several thousand prisoners from a local prison, potentially adding more fighters to their cause.

Stretching from the north of Mosul through Tikrit to the south and toward Baghdad along the Tigris River Valley, ISIL is striving to maintain a continuous line of pressure running through what is practically the northern spine of populated Iraq. The Tigris River Valley contains a number of key strategic energy areas, including the oil refinery near Baiji. Although the refinery is still under state control at this time, the areas where ISIL is operating largely match areas where al Qaeda in Iraq was active during the height of the Sunni insurrection in Iraq from 2004-2006. As opposed to a first-time assault or new offensive, ISIL's actions speak more of a resurgence into historical areas of operations.

As well as continuing to push forward, the Islamic State in Iraq and the Levant will largely seek to avoid stand-up fights against well-equipped and determined Iraqi army units, though they have held their ground against such forces in Al Fallujah and Ar Ramadi. The wide-ranging, mobile and rapidly dispersed ISIL forces have a key advantage when it comes to maneuvering in battle over the slower, mechanized units of the Iraqi army. While ISIL maximizes its impact against a disorganized Baghdad, the jihadist group seeks to consolidate its control over territory in heavily Sunni areas, where it has already made significant inroads with the local population. Ambitiously, these areas of control could include large portions of the north as well as Anbar Province. More realistically, it would mean greater ISIL presence in the longer term and, in some cases, direct control in Anbar and possibly other provinces such as Nineveh and Salah ad Din. Working toward this goal, the Islamic State in Iraq and the Levant will continue to focus on its revitalized effort to dismantle the Awakening movement, a coalition of tribal elements that was instrumental in pushing al Qaeda in Iraq out of Anbar the first time, drawing Sunni tribes back into its fold in the process.

The Iraqi army is attempting to contain the ISIL threat that is rapidly spreading into Salah ad Din and Kirkuk provinces. Iraqi forces, supported by allied tribal elements, have reportedly struck back against ISIL outside As Samarra and in Tikrit. A number of Iraqi army units are also supposedly withdrawing from Anbar province, which will further reduce pressure on ISIL-held cities there. These forces are reportedly focusing on the northern approaches to Baghdad, while the Iraqi government is attempting to pull together all reserve units capable of quickly moving to the fight. For all intents and purposes the Iraqi army is overstretched, the geographic dispersion of threats outmatching its resources. This means that Baghdad must prioritize its goals in the fight against ISIL.

Protect the Core

The most important priority for Baghdad right now is to secure its capital and oil infrastructure and begin pushing north to meet ISIL units approaching from Mosul down the Tigris River Valley. This does not mean that the Islamic State in Iraq and the Levant can be eradicated from these areas: Small ISIL cells will continue to operate across the region, and indeed in Baghdad itself. It does mean, however, that the Iraqi army will try to disrupt large mobile ISIL columns seeking to raid and to establish control over towns and cities. By concentrating its forces, the Iraqi army campaign in Anbar, especially around Ar Ramadi and Al Fallujah, will inevitably be at a disadvantage as it falls to a level of secondary importance. The campaign to rid Iraq of ISIL, which was never realistic so long as the jihadists held a virtual sanctuary in eastern Syria, becomes even more tenuous over the long term.

In the fight against the Islamic State in Iraq and the Levant, Baghdad holds a potential advantage, but one which the al-Maliki government has been loath to use so far. This advantage is a greater reliance and cooperation with the Peshmerga (Kurdish security forces) in a combined fight against the jihadists. For political reasons ranging from disputes over territory to energy resources distribution, the central government in Baghdad had sought to maximize its direct control over the north, while minimizing the Kurdish security presence beyond Kurdistan Regional Government-administered areas. With ISIL making alarming gains in the north, it is now far more possible that the central government in Iraq would seek to cooperate with the Peshmerga in a combined push on ISIL in Kirkuk and Mosul. To that end, the Iraqi parliamentary speaker reportedly mentioned the possibility of coordinating with Kurdistan Regional Government President Massoud Barzani. Kurdish Peshmerga forces are reportedly mobilizing in preparation for defensive as well as offensive operations against ISIL.

The Bigger Picture

Beyond Iraq, a number of countries are immediately affected by ISIL. The Syrian battle space bleeds heavily into Iraq due to a porous border, accelerated by the almost total collapse of Syrian army border crossing posts. Since January, ISIL has been heavily involved in fighting with more moderate Syrian rebel factions, as well as with Jabhat al Nusra, the official al Qaeda franchise in Syria. As the fighting has worn on, ISIL has gradually released its hold in western Syria and turned its attention to the Raqqah and Deir el-Zour governorates. Deir el-Zour was particularly important for ISIL as it allowed it to maintain a direct supply link with its established presence in western and northern Iraq, especially in Anbar province. Through this supply link, ISIL has been able to transfer experienced foreign fighters and captured Syrian army equipment to Iraq, including vehicles and anti-tank guided munitions. It has also replenished its stock of ammunition and explosives, greatly aiding operations in Iraq.

The Syrian conflict is affected by the ISIL push in Iraq in two ways. The first is that the jihadists may divert large numbers of fighters from Syria to its Iraq push, which would open ISIL to more pressure in Syria. The second impact is the withdrawal of large numbers of Iraqi Shiite militants — men that have been fighting alongside the Syrian army — leaving to concentrate their efforts back home against ISIL. Such a withdrawal would be unpopular in the Syrian regime because it would take away an important source of manpower.

Regional Interest

Ankara is also watching the events in Iraq with considerable attention. Not only are Turkish citizens directly implicated in the conflict, with a number of Turks reportedly seized by ISIL militants, but the Turkish government also maintains an important stake in energy development in northern Iraq. Ankara has long been involved in politics between Baghdad and the Kurdistan Regional Government on issues surrounding the delivery of energy. Turkey is also increasingly concerned about the growing reach of ISIL and has already clashed with militants on its border with Syria. Turkey is especially wary of the potential for attacks by ISIL — attacks that would exploit the long border that runs from the Mediterranean to Iran. While Turkey has been hesitant to directly send forces against ISIL in Syria, the fact that the Islamic State in Iraq and the Levant has seized large numbers of Turks — including the consulate staff from Mosul — may push Ankara to become more directly involved in the crisis.

Iran has long sustained the regime in Syria, as well as indirectly supporting al-Maliki's government in its fight against Sunni jihadists in Syria and Iraq. The growing reach of ISIL, and its ever-closer presence to Iran, is sure to raise considerable anxiety in Tehran. Iran can therefore be expected to further bolster its support for al-Maliki as well as for Shiite proxies across Iraq. In supporting al Maliki's fight, Tehran finds itself very much aligned with Washington.

The United States will avoid sending significant forces back into Iraq, but Washington will ramp up its efforts to contain the ISIL threat by delivering vital equipment such as helicopter gunships, Hellfire missiles, communications equipment, large volumes of small arms and ammunition. This assistance, coupled with a common regional interest to contain the Islamic State in Iraq and the Levant, will likely contain the threat to northern and western Iraq. Though Iraq's southern energy corridor will probably be spared, the Sunni belt in central Iraq and the territories disputed between the central government and the Kurdistan Regional Government will face rising sectarian stress, in line with ISIL's designs for the region.