A suicide bomber killed five senior commanders of the powerful Iranian Revolutionary Guard and at least 37 others Sunday near the Pakistani border in the heartland of a potentially escalating Sunni insurgency. Sunni rebels known as Jundallah, or Soldiers of God, reportedly have claimed responsibility for the attack. Because of ruthless police enforcement, there is not much of this activity in Iran—at least not at this level. But, by encouraging this kind of activity elsewhere, the Iranians are bound to reap what they sow—and they are.