ISIS says it has ramped up suicide attacks due to its recent losses on the battle field.  This is entirely consistent with the instrumentalist view of terrorism, that is, terrorism is undertaken to achieve political objectives with a strategic logic and is not the result of mental illness, nor is it random. It is a tactic used in conflict typically from a position of weakness. Its key feature is that the targets are civilians, other non-combatants, or civilian installations, explicitly ignoring the just war principle of civilian immunity.

Suicide terrorism has its own strategic logic that is tied to the hardness of the target. As counter-terrorism operations improve security, the terrorist organization escalates to suicide terrorism in order to demonstrate (a) to its adversary the ability to still terrorize its victims, (b) to its supporters that it is still relevant to the cause. Religiously motivated terrorist groups are rational economic actors.  The resort to suicide tactics is a sign that other less expensive options have been foreclosed.

In the case of ISIS it must project the image of a successful Islamic insurgency that will result in the establishment of an Islamic state. To fail would risk the dissolution of the movement as various Sunni salafist jihadi and takfiri organizations would seek a stronger horse to back in the battle against the nearest enemies (Marxists and Shi’ites) and the far enemies (Europeans and Americans).