A somber weariness has settled in across Western democracies in the aftermath of the Paris attacks. Defeating and destroying the so-called Islamic State with military force has won broader support. But most realize that the challenge will require a complex set of policy responses, far beyond aerial bombardments to liberate territory controlled by the group in Syria and Iraq. Although there is not yet any consensus about what such a long-term strategy should look like, some new ideas are emerging.

To begin with, the old debate over how to distinguish between the threat posed by al-Qaida and the newer one from the Islamic State has been overtaken by the events in Paris earlier this month. Only a few months ago, some U.S. officials were fretting that they had misallocated resources to al-Qaida, perceiving it as the more established, lethal danger, at a time when it still seemed the Islamic State was more focused on holding Arab territory than confronting the West. The concern was that the U.S. and its European allies had developed an intelligence and military infrastructure that were not a perfect match for the larger danger that the Islamic State has become, first in the Arab heartlands and now in Western capitals.

To continue reading, click here.