Members of al Nusra Front drive in a convoy as they tour villages, which they said they have seized control of from Syrian rebel factions, in the southern countryside of Idlib, December 2, 2014. (Khalil Ashawi/Reuters)

Radical Islamist groups have flourished in the civil wars in Syria, Iraq, Afghanistan, Libya and Yemen and it’s not clear why. Al Nusra Front had no real presence in Syria until civil war broke out in 2011. The same could be said of the Islamic State, yet today it has won out over more moderate groups to become the dominant militant faction fighting in Syria and Iraq. This pattern is not unique to the Middle East. Since 2007, the number of violent Islamist groups in the Middle East and Africa has significantly increased and has spread to include most of North Africa, the Democratic Republic of the Congo, Tanzania, Kenya and South Sudan.

On Feb. 18, the Obama administration will hold the “Summit on Countering Violent Extremism” to try to understand this trend and determine what the United States can do about it. This is a formidable challenge. According to Maj. Gen. Michael Nagata, commander of U.S. Special Operations forces in the Middle East: “We do not understand the movement [Islamic State], and until we do, we are not going to defeat it.”

Political science and economics offers at least three insights into why rebel groups may have incentives to adopt an extreme ideology.

  1. First, an extreme ideology can give rebel organizations a recruiting advantage. The ideological extreme is where a group is more likely to find individuals willing to fight and die for a cause. The more polarized a society, the more likely this strategy is to work.
  1. Second, an extreme ideology can reassure a population that a particular rebel group will remain honest and not “sell out” once in power. This is especially important in countries with a history of repressive governments and dishonest leaders. The more distrustful a population is of its government, the more likely this strategy is to work.
  1. Third, an extreme ideology is a way for groups to distinguish themselves from a competitive field of similar-looking rebel factions. Adopting the position as the “most Islamic” group has natural advantages. Few potential recruits motivated by a desire to protect Islam will be excited about joining the second most Islamic group. In addition, it is much easier to criticize other groups for failing to commit to Islam if you have already claimed the position of “most Islamic group.” The greater the number of competing factions in a civil war, the more likely this strategy is to work.

These strategies are particularly effective at this time in the Middle East because the region contains all of the conditions conducive to extremism. First, most countries in the region are polarized along sectarian lines and civil war intensified these rivalries. This has placed a greater percentage of the population at the more radical extreme, where the recruitment of soldiers is easier. Second, most countries in the Middle East have a history of bad government. This creates an opening for rebel groups to use extreme ideology as a way to credibly commit to more accountable and just rule once in power. Third, the civil wars in Libya, Syria, Iraq, Afghanistan and Yemen have created a situation in which multiple rebel factions are competing with each other for local support and international financing. This is exactly the situation in which differentiating yourself from your rivals becomes important.

So what should the United States do to counter extremism? First and foremost, provide hard evidence to local populations that radical groups will not rule as fairly and honestly as they claim they will. Outsiders can also help moderate groups devise their own costly signals that they will govern impartially and benevolently once in power. Enhancing the credibility of these moderate groups should help recruit the support of those citizens whose beliefs are more aligned with them and undercut the support of extremists. Moderate groups will also require more practical, material assistance to compete effectively with extremist groups that draw funding from wealthy like-minded donors abroad.

The United States will not be able to stop the Islamic State or any of the extremist groups that have emerged in the Middle East until it understands why these groups are succeeding at this time. They are succeeding because the Middle East is home to some of the most corrupt, ineffective and exclusionary governments in the world. As a result, their populations are looking for new, more trustworthy leaders. Key to countering extremists, therefore, will be to help moderate groups communicate their ability and their desire to govern more effectively than past incumbents while providing evidence that extremists will not. Provide this evidence, and you eliminate the source of radical Islam’s strength and appeal.

Barbara F. Walter is a professor of political science at the Graduate School of International Relations and Pacific Studies at the University of California, San Diego.