Not really. Ever since the Caliphate was abolished after the fall of the Ottoman Empire, Islam has been without a “Magisterium” so to speak. This has had the effect of emboldening mullahs to speak authoritatively and issue these ‘fatwas’ since there is no authority structure to correct them if/when they go astray. So if one mullah issues a fatwa calling for the killing of an infidel, no other mullah really has any particular authority to restrain him, other than pure power of moral persuasion (which is not negligible).