What Happens When ISIS Goes Underground?

A view of Islamic State slogans painted along the walls of a tunnel near Mosul, Iraq, March 4, 2017. Reuters/Alaa Al-Marjani

Defeating the Islamic State could be the marquee foreign-policy accomplishment of the Trump administration. Doing so, however, will require more than just forcing the caliphate underground.

January-February 2018

The Islamic State recognizes its own pitiful position. As the group lost more of its strongholds, its rhetoric shifted to dismiss the importance of territorial control. Instead, the Islamic State emphasized the concept of a caliphate as the driving force behind the group’s success. Abu Muhammad al-Adnani, the Islamic State’s spokesman and senior operational figure, stated in a May 2016 recorded message,

“O America, would we be defeated and you be victorious if you were to take Mosul or Sirte or Raqqa? . . . Certainly not! We would be defeated and you victorious only if you were able to remove the Quran from Muslims’ hearts.”

Like so many other Islamic State leaders, al-Adnani is now dead.

AS THE Islamic State crumbles, its leaders will try to continue fighting rather than surrender. They plan to regroup, maintain their relevance and eventually resurge, through a mix of international and regional terrorism and local insurgency, while keeping their cause alive.

The Islamic State is not a stranger to defeat: it emerged out of Al Qaeda in Iraq, which for several years was on death’s door. In June 2010, Gen. Ray Odierno, then the commander of U.S. forces in Iraq, noted that in the last ninety days U.S. and Iraqi forces had “either picked up or killed 34 out of the top 42 Al Qaeda in Iraq leaders.” The two top Al Qaeda in Iraq leaders died in a firefight that year. By 2011, CIA director Leon Panetta declared, “we’re within reach of strategically defeating al-Qaeda.”

In response, Al Qaeda in Iraq focused on terrorism—in Iraq, not abroad—to stay relevant and to intimidate its enemies. It waged a campaign of assassination against opposing tribal leaders and other Sunnis who cooperated with the Iraqi government, killing more than 1,300 Iraqi leaders from 2009 through 2013. Due to terrorism and local killings, many Iraqis distrusted their government to secure peace and feared openly defying the jihadists. Al Qaeda in Iraq’s patience paid off: over time, the Iraqi government stepped up discrimination against Sunnis and the Syrian Civil War offered a sanctuary across the border. Taken together, these two factors allowed the group to rebuild.

The Islamic State will try to repeat this success. Al-Adnani referred to a “retreat into the desert” to rebuild forces in order to prepare for upcoming battles. This mirrors jihadis’ relocation to remote areas along Iraq’s borders after the 2007 U.S. surge.

Unfortunately, both Iraq and Syria offer promising areas for a rebirth. In Iraq, the government in Baghdad repeatedly implemented policies that discriminated against Sunnis while lacking the strength or support necessary to impose order on an unhappy population—in other words, it cannot coerce, and it seems unwilling to coopt. Shia militias are occupying many Sunni areas where the Islamic State once held sway. Already the Baghdad government is exchanging fire with Kurdish forces. Shia militias are committing abuses against local Sunnis in areas they conquered from the Islamic State. Revenge killings are common.

In Syria, the situation is even worse, with the regime of Bashar al-Assad committing unspeakable atrocities against Sunni Muslims. Tribes, Kurdish groups and other local actors that have worked with America against the Islamic State often regard each other as enemies, or at least have different interests, which will inhibit their ability to cooperate against Islamic State remnants. As their shared enemy declines and the competition for local power increases, these groups are more likely to war against each other. As such, the Islamic State will likely find many openings to exploit, allowing it to relieve pressure and ensure at least some sanctuary. In the scramble for power, many local groups may even shift from enemy to temporary ally.

To defeat the Islamic State as an underground insurgency, someone must develop good governance in its former territories in Iraq and Syria, convincing locals to help uproot the group—an unlikely feat for which there are no credible volunteers. Unlike its previous revival, the Islamic State now has two countries where it can exploit problems, as opposed to just Iraq in the past.

The Islamic State will probably further regionalize the conflict and seek opportunities beyond Iraq and Syria. Already the group regards Iraq and Syria as one theater, shifting assets between the two countries depending on its perceived dangers and opportunities. The group also maintains an extensive network in Turkey, and has attacked Jordan, Lebanon and Saudi Arabia, among other countries. The Islamic State will probe these areas for weaknesses, using its operatives and local supporters to conduct attacks and develop an enduring presence.

Most troubling for the long term, the Islamic State has nurtured the flame of jihad around the world. Even as the group declines, the ideas it champions—the necessity of a caliphate, the glory of brutality and the evil of Western states—have spread further, as the staggering volume of foreign fighters suggests. The Islamic State’s propaganda is extensive and almost ubiquitous. It, or would-be successor organizations, will try to harvest the ideas that the early Islamic State leaders planted.