Kerry called for a "global coalition" to fight ISIS.

Fighting ISIS in a way that is effective in the long term is not such a simple thing. Previous interventions backfired, and ISIS is the result.

Although fighting ISIS can hurt it tactically, in the long term military opposition that enrages foreign Sunnis is what ISIS thrives on.

The leaders of ISIS seem to want to encourage a big US intervention, and that is why they publish provocative videos of real or pretended beheadings.

They also want to encourage Shi'ite hatred that will frighten Iraqi Sunnis.