Bashar Assad does not need to use chemical weapons to successfully defeat rebel forces in an upcoming battle. However, for a number of reasons, he is likely to do so anyway.

This bears consideration following national security adviser John Bolton’s warning to his Russian counterpart last week, when he said that the U.S. will conduct military strikes against Assad’s regime if he again uses chemical weapons against his people. As Bloomberg reports, that warning is rooted in U.S. intelligence indicating Assad is preparing to use chemical weapons in Idlib province. That province is the last remaining redoubt of the rebellion against Assad’s rule and faces an imminent Russian-Iranian-Assad assault.