Five years ago, during the hopefully named Arab Spring, Syrians staged peaceful protests against the ruling dynasty that had long oppressed them. President Bashar al Assad responded brutally: In May 2011, he sent tanks into the suburbs of Damascus, Deraa, Homs and other cities to crush his critics. Civil war followed.
Experts, not least those in the US government, convinced themselves that the rebels would prevail. There were simply too many angry Syrian Sunnis and President Assad, a member of the Alawite minority, had too few loyal troops. Before long, Sunni jihadis from abroad began streaming into Syria to support the rebels. Among them were branches of al Qaeda, one of which splintered into the Islamic State.
Events then took an unexpected turn. Iran’s rulers, self-proclaimed Shia jihadis, regarded Mr. Assad as their most important ally in the Arab world — or, perhaps more precisely, a regent of their expanding empire. So they instructed Hezbollah, their loyal Lebanese Shia militia, to deploy fighters to Syria to defend him.