ISIS declares "Caliphate," calls on groups to pledge their allegiance

The military success of ISIS has emboldened the radical military group to declare "Caliphate" - an Islamic state spanning large areas from Syria to Eastern Iraq and calling on other muslim groups to pledge their allegiance. The group also posted several propaganda videos online showing evidence of their advances against the Iraqi military. CNN's John Berman speaks with Senior International Correspondent Arwa Damon and Former FBI Supervisory Special Agent Ali Soufan about the latest on ground and how significant is ISIS' claim to leadership of the global Islamist movement.