After spending so much time in isolation

The Iranian-dominated Shia arc has collapsed. The keystone to the arc was Bashar al-Assad’s regime and the partnership that his father Hafiz al-Assad forged with the Iranian regime in the 1980s.  That alliance gave Tehran for decades its only state-level Arab ally, one that shares a border with Israel.   It was also critical in enabling supply of Hezbollah and providing forward bases and freedom of movement for Islamic Revolutionary Guard personnel.