If Assad falls and a new government is formed by Sunni rebel forces, Iran loses a keystone in its regional power structure.
It appeals to angry Sunni Arabs who are less than a third of Iraqis.
But the essential conditions that led Hamas to realign itself with the Sunni Muslim states remain in place.
1620s, from Arabic, literally "lawful," from Sunna "traditional teachings of Muhammad," literally "way, custom, course, tradition." Muslims who accept the orthodox tradition as well as the Quran.