The reason that Islamist militants can assert that jihad is necessary against the perceived enemies of Islam is that there is sufficient ammunition in the Quran to buttress their beliefs. The same could also, of course, be said for the Old Testament, which is full of scenes of violent death visited on the enemies of God.

Islam is, to be sure, a big tent, and the one and a half billion Muslims in the world run the gamut from mystical, moderate, pacific Sufis to Salafists.

Certain Gulf Arabs support proxy jihadist Sunni groups such as al Qaeda's affiliate in Syria, while Iran supports Shia militant forces such as Hezbollah.

Peter Bergen Quotes