How to Fight the Islamic State

CAMBRIDGE – The Islamic State 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 jihadists from around the world.

US President Barack Obama says that the Islamic State must be degraded and ultimately defeated. He has appointed General John Allen to lead a coalition of some 60 countries in the task, relying on air strikes, 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 US 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 US and its allies now face.

The Islamic State 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 US-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 Shia and Sufi Muslims, whom it considers “takfir,” or not true Islamic monotheists.