One of the few public discussions of how unconventional warfare might be useful against the Islamic State came in an Oct. 20 post on War on the Rocks, my favorite military blog. Clint Watts, a former Army officer and FBI special agent, describes various ways to encourage dissension and division. “Try to put a wedge between [the Islamic State’s] Iraqi dominated leadership and its foreign fighter troops,” argues Watts.

Atheel al-Nujaifi, the governor of Iraq’s Nineveh province, told me in an interview Monday that friction between foreigners and locals has already begun among the jihadists in Mosul, along with tension between Turkmen and Sunni Arab members of the group.

Watts also suggests encouraging rivalry between the criminal thugs gravitating toward the Islamic State and the group’s core of religious zealots. And he proposes sending infiltrators (or reports of infiltrators) to make the extremists “paranoid about spies” in their ranks. Such double-agent tactics have worked in Somalia and Algeria, he says.