It is – to quote US President Barack Obama’s description of what motivated a married couple of Pakistani origin to carry out the recent mass shooting in San Bernardino, California – a “perverted interpretation of Islam,” and the ideological mother of jihadist terrorism. Its offspring include Al Qaeda, the Taliban, Boko Haram, al-Shabaab, and the Islamic State, all of which blend hostility toward non-Sunnis and anti-modern romanticism into nihilistic rage.