Complex sentence: Not only is the succession to the throne subject to the approval of the ulema, so are all new laws (royal decrees), and they have an influential role in major government decisions, the judicial system, education policy and the enforcement of religious morals.
Split into simpler sentences: Not only is the succession to the throne subject to the approval of the ulema, so are all new laws (royal decrees). They also have an influential role in major government decisions, the judicial system, education policy and the enforcement of religious morals.