@Jonathan Drake - the Quranic verse that says 'I will cast terror into the disbelievers; therefore, strike at their necks and strike off the fingertips of them' is given different interpretations. Most imams interpret this verse in context - making any jihad for muslims internal. Extremist imams, and groups like ISIS and Al Qaeda, interpret this verse as a literal, open-ended command to kill disbelievers (in reality anybody outside their group).
Surely, you have to admit that both interpretations are plausible.