In the wake of the nuclear accord with Iran, Saudi Arabia has not been content to simply wait and see what shape regional developments take. Its goal is to build a Sunni, Arab coalition that can counter the imposing shadow Iran is casting over the region. Saudi Arabia is already combating Iran on multiple, consequential fronts: The kingdom leads a broad coalition of regional powers pushing back against the Iran-backed Houthi advance in Yemen, it supports numerous anti-Assad rebel groups in Syria and it pays Arab Sunni Iraqi tribes to convince them to fight the Islamic State. The warming of ties with Hamas, like Riyadh's recently improved relationship with Sudan, is a less overt tactic in pursuit of the same overall goal. Backing Hamas can help Saudi Arabia's regional alliance against Iran in three ways.