Civilian children stand next to a burnt vehicle during clashes between Iraqi security forces and ISIS in the northern Iraq city of Mosul, June 2014.
Civilian children stand next to a burnt vehicle during clashes between Iraqi security forces and ISIS in the northern Iraq city of Mosul, June 2014.

Since October, the Islamic State (or ISIS) has appeared to be on the verge of defeat. Yet even if ISIS were never to reemerge, the United States is no more secure against the jihadist threat than it was in the past. ISIS is just one of hundreds of Islamist extremist groups that have formed since 2011. All of these groups have similar goals centered around creating a transnational caliphate using military force, and all of them see the United States as standing in their way. In the event of ISIS’ defeat, numerous additional Salafi jihadist organizations will be ready to take its place as long as the conditions that gave rise to the group persist.

One of the major trends over the last six years has been the rise of Islamist extremist groups fighting in civil wars in Muslim-majority countries. By 2016, Salafi jihadist groups made up approximately 35 percent of all major militant groups in Iraq, 50 percent of major militant groups in Somalia, and 70 percent of the groups in Syria.

The primary reason for this rise in jihadist organizations is the sharp increase in the number of civil wars in Muslim countries since 2001. Historically, civil wars have proven to be a breeding ground for this type of extremism. In fact, as long as the current conflicts continue in Chad, Iraq, Libya, Mali, Nigeria, Pakistan, Somalia, and Syria, the Islamist insurgents that have emerged in these wars will also endure.

Civil wars create weakened or failing states—gray zones—where nonstate actors can operate and build their support. This is exactly the environment in which many of the world’s worst terrorist groups, including Hamas, al Qaeda, and ISIS, first began to thrive. Today, the main threat from al Qaeda and its franchises stems entirely from ungoverned states experiencing violence and instability. Extremist groups’ efforts to gain traction in more stable countries such as Egypt, Jordan, Morocco, and Saudi Arabia continue to fail.

Terrorist groups tend to thrive in civil wars because the environment of uncertainty and insecurity is ready-made for them. Extremist ideologies such as Salafi jihadism can help rebel elites solve three organizational challenges that then allow them to outcompete moderate groups. The first is the potentially debilitating problem of taking collective action. To mobilize and maintain an army, rebel leaders must convince at least some individuals to pay the high costs of fighting, a requirement that most people would prefer to avoid. Normally, rebel organizations attempt to overcome such problems by offering recruits private rewards in the form of money, security, or access to plunder. But extremist groups, especially faith-based ones, have a particular advantage because they can offer cheap, deferred compensation in the form of an eternal afterlife or rewards in paradise. They can also promise a potentially devastating type of personal punishment (eternal damnation in the case of Christianity and excommunication in the case of Islam) that is both costless to enforce and perceived as impossible to escape.

The second organizational challenge has to do with the principal-agent problem, which arises when rebel leaders (the principals) have to delegate responsibilities to soldiers (agents) they do not entirely control. To avoid defeat, elites must recruit volunteers who will remain loyal to the organization even after they are deployed to the field. An extremist ideology can help screen out less committed soldiers, which then reduces the problem of poor performance, side switching, and betrayal. Rebel leaders can also use the ideology to signal their own dedication to a cause, allowing them to attract more devoted and hard-fighting soldiers to their ranks.

The third organizational challenge is related to a group’s commitment to political reform. To successfully compete against other factions fighting a war, rebel leaders have to reassure their soldiers and supporters that they will resist corruption once in power. This is especially important in countries with few institutional constraints on government elites and a history of exploitation. An extremist ideology, especially one that demands personal sacrifices from its leaders, could serve as a way for rebel elites to credibly commit to more principled behavior once in power. Taken together, these three challenges could help explain why extremists might outperform moderate groups in terms of recruiting soldiers and supporters even in environments where the preferences of most citizens are not extreme.

All of this suggests that rebel leaders and moderate citizens need not believe in an ideology to embrace it. Groups such as ISIS, al Qaeda, and Jabhat al-Nusra have emerged in Muslim countries not because average Muslims are more ideologically extreme than the rest of us but because these are the countries where citizens are trying to depose long-standing authoritarian regimes and where the conditions that encourage these types of groups currently exist.

Rebel leaders and moderate citizens need not believe in an ideology to embrace it.

Salafi jihadist groups proliferated in most of the civil wars fought in Muslim-majority countries since 2003 because their particular ideology represented the sweet spot for the strategic use of extremism discussed above. Organizations such as ISIS that emphasize justice, honor, and a lack of corruption appealed to a large part of the population in Muslim countries such as Iraq and Syria with a history of repressive regimes. Citizens were looking to identify those leaders who had some chance to remain true to a just Islamic state, and these groups’ extremist ideology addressed the concerns of more moderate citizens that leaders would not become corrupt once in office. The language of Islam used by these groups had resonance in many of these civil war–torn populations, even if most did not accept the Salafi jihadist ideology. Former Jamaat al-Tawhid wal-Jihad leader Abu Musab al-Zarqawi was the first to use these advantages to outcompete other Sunni groups. Going forward, others will use these tactics as well.

This means that ISIS-style groups will continue to emerge in these countries as long as the conditions that gave rise to them are still present. It also means that there are strong incentives for rebel leaders to embrace an extremist ideology in any country, Muslim or not, experiencing civil war with a history of corruption and few constraints on power. ISIS was one of the first groups to figure out this strategy, but others will follow. 

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  • BARBARA F. WALTER is Professor of Political Science at the University of California–San Diego’s School of Global Policy and Strategy.
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