If Abdullah is made from the same iron as his father ISIS could be in for a very bad time. They should ask the PLO about Black September. Of course it could depend on whether the Jordanian Army of 2015 is still made up of bedouin devoted by tribal ties to the descendant of The Prophet. And whether they still maintain the same e sprit as was instilled by John Glubb. One can ask Israeli vets of 48 how much fun it was going against the Jordanians and even in 67 taking of the West Bank was a chore the IDF would not want to repeat.
ISIS has gotten Jordan’s lather up. I don’t thing they thought this through, or if they did their assumptions can’t be sound.