In the Washington Post, Adam Taylor talked to several scholars about how IS was changing the rules in the Middle East.

“Americans are understandably reluctant to help Assad because he is a depraved dictator who responded to the Arab Awakening by turning his military against the Syrian population,” he quotes Max Abrahams, a terrorism policy expert from Northeastern University, as saying.

Still, he says there’s a political calculus at play when it comes to the safety of American citizens.

“Whereas Assad has never posed a direct threat to the US homeland, IS is actively scheming to carry out a mass casualty attack against us. From a US national security perspective, IS is the more immediate threat.”