The so-called Islamic State of Iraq and Syria barbarically beheaded Western civilians and put out videos of the murders for the world to see—inviting, it seemed, the United States and Western countries to intervene militarily. It has killed countless Christians, Yazidis, and Shi‘a Muslims, whom it considers infidels, and it has imposed a brutal form of shari’a law in the territory it controls. It rules by terror, engaging in public floggings and executions and amputating the hands of thieves.

There is no doubt that the rise of ISIS is frightening. But as New York Times columnist Thomas Friedman notes, fear is not a good guide to policy. Fear makes people exaggerate risks and often act in ways that make the situation worse.

The key policy question is not how frightening and troubling ISIS is, but what actual threat it poses to the United States and to the stability of the Middle East. And the next question is: What can the United States best do to contain that threat without causing more harm? On this issue, President Obama has rightly said—even as he prepared to authorize air strikes—that “there’s no American military solution” to the crisis ISIS presents.