Joseph S. Nye

ISIS has captured the world’s attention with gruesome videos of beheadings, wanton destruction of antiquities and skilled use of social media.

It has also captured a large part of eastern Syria and western Iraq, proclaimed a caliphate based in Raqqa, Syria, and attracted foreign Islamist extremists from around the world.

U.S. President Barack Obama says that ISIS must be degraded and ultimately defeated. He has appointed Gen. John Allen to lead a coalition of some 60 countries in the task, relying on airstrikes, special forces and training missions. Some critics want him to send more American troops; others say that the United States should settle for a doctrine of containment.

In the current U.S. presidential campaign, some candidates are calling for “boots on the ground.” They are right: Boots are needed. But the soldiers who wear them should be Sunni Arabs and Turks, not Americans. And that says a lot about the nature of the triple threat that the U.S. and its allies now face.

ISIS is three things: a transnational terrorist group, a proto-state and a political ideology with religious roots. It grew out of Al-Qaeda after the misguided U.S.-led invasion of Iraq; and, like Al-Qaeda, it appeals to extremist Sunni Islamists. But it has gone further, by establishing a caliphate, and is now a rival to Al-Qaeda. Its possession of territory creates the legitimacy and capacity for offensive jihad, which it wages not only against infidels but also Shiites and Sufi Muslims, whom it considers “takfiris,” or not true Islamic monotheists.

ISIS extols the purity of seventh-century Islam, but it is extremely adept at using 21st-century media. Its videos and social-media channels are effective tools for attracting a minority of Muslims – primarily young people from Europe, America, Africa and Asia – who are struggling with their identity. Disgruntled, many are drawn to “Sheikh Google,” where ISIS recruiters wait to prey upon them.

By some estimates, there are more than 25,000 foreign fighters serving in ISIS today. Those who are killed are quickly replaced.

The tripartite nature of ISIS creates a policy dilemma. On the one hand, it is important to use hard military power to deprive the caliphate of the territory that provides it both sanctuary and legitimacy. But if the American military footprint is too heavy, the soft power of ISIS will be strengthened, thus aiding its global recruiting efforts.

That is why the boots on the ground must be Sunni. The presence of foreign or Shiite troops reinforces the ISIS claim of being surrounded and challenged by infidels. So far, thanks largely to effective Kurdish forces, who are overwhelmingly Sunni, ISIS has lost some 30 percent of the territory it held a year ago. But deploying additional Sunni infantry requires training, support and time, as well as pressure on Iraq’s Shiite-dominated central government to temper its sectarian approach.

After the debacle in Libya (where ISIS supports extremist militias and has announced the creation of three “distant provinces”), Obama is understandably reluctant to overthrow Syrian President Bashar Assad’s regime, only to see ISIS take control of more territory, accompanied by genocidal atrocities against Syria’s many non-Sunnis. But Assad is one of the most effective recruiting tools of ISIS. Many foreign extremists respond to the prospect of helping to overthrow a tyrannical Alawite ruler who is killing Sunnis.

The U.S. diplomatic task is to persuade Assad’s supporters, Russia and Iran, to remove him without dismantling the remains of the Syrian state structure. A no-fly zone and a safe zone in northern Syria for the millions of displaced people could reinforce American diplomacy. And providing massive humanitarian assistance to the refugees (at which the American military is very effective) would increase U.S. soft power enormously.

As it stands, the funding and coordination of America’s soft-power strategy is inadequate. But we know that hard power is not enough, particularly to contest the cyber territory that ISIS occupies – for example, by developing a capacity to take down botnets and counter hostile social-media accounts.

Even if the U.S. and its allies defeat ISIS over the coming decade, we should be prepared for a similar Sunni extremist group to rise from the ashes. Revolutions of the type the Middle East is experiencing take a long time to resolve. The sources of revolutionary instability include tenuous post-colonial boundaries; arrested modernization; the failed “Arab Spring”; and religious sectarianism, exacerbated by the interstate rivalry between Sunni-ruled Saudi Arabia and Shiite-ruled Iran.

In Europe, wars of religion between Catholics and Protestants lasted for nearly a century and a half. The fighting ended (with the Peace of Westphalia in 1648) only after Germany lost a quarter of its population in the Thirty Years’ War.

But it is also worth remembering that the coalitions of that time were complex, with Catholic France aiding Dutch Protestants against Catholic Habsburgs for dynastic rather than religious reasons.

We should expect similar complexity in today’s Middle East.

Looking ahead in a region where the U.S. has interests as varied as energy, Israel’s security, nuclear non-proliferation, and human rights, American policymakers will need to follow a flexible strategy of “containment plus nudging,” which implies siding with different states and groups in different circumstances.

For example, whether or not Iranian policy becomes more moderate, sometimes Iran will share U.S. interests, and sometimes it will oppose them. In fact, the recent nuclear agreement may open opportunities for greater flexibility. To seize them, however, U.S. foreign policy toward the Middle East will have to develop a higher level of sophistication than the current debate reveals.