If ever there was an opportunity to set Islamic terror back a couple of decades that opportunity is now in the wastelands of Syria and Iraq.
The Islamic State is estimated to have 15,000 fighters out there beheading and crucifying and raping assorted minorities and lots of other Muslims. They have a few ranks and APCs plus a fair bit of heavy weaponry and lots of cash. (Though given the intelligence failures of the current American regime it would be wise to double those estimates.)
A division of Marines and serious air strikes – think cluster bomb more than precision munitions get will stop IS and then Saudi financed Egyptians and Pakistani infantry can go in and kill them. Not capture, not take as prisoners, kill. The actual killing needs to be done by their fellow Muslims and it needs to be done pretty much immediately.
Soft power has been proven bullshit. Time to let Is know what happens to bullies.