Abu Mohammed al-Julani, leader of the Al Qaeda-affiliated Syrian rebel A-Nusra Front, has virtually declared war on the rival Iraqi al Qaeda (ISIS): either accept clerical arbitration within five days, or be expelled from Syria “or even Iraq.” The Nusra threat followed the killing of an al Qaeda emissary, Abu Khaled al-Suria, along with several members of his Ahrar al-Sham group, in a suicide attack on its Aleppo headquarters Sunday.