Obama created ISIS. If we had not removed all troops from Iraq and armed the predecessors of ISIS, they may not exist.
More directly than that.
Obama forced a renaming of Al-Qaeda to ISIS because Benghazi was an illegal/unconstitutional gun-running operation to supply military arms to the rebels in Syria, who was Al Qaeda.
This is why Hillary! and Obama allowed Americans to be slaughtered. If they saved those Americans, it was too great a risk that the gun running would be exposed, and that Hillary and Obama would be guilty of high treason (in the literal sense) for supplying military arms to people we are at war with.
So, one of their legalistic loopholes was to rename Al Qaeda “ISIS” so that they weren’t supplying arms to Al Qaeda but some completely different group, that they can spin was on our side all along (or so they thought) — all BS of course.