I know you think you've found a bargain that nobody else noticed hidden in a back corner of the used car lot. Let me warn you: it's a clunker. Here, I'll list the defects. You can have your own mechanic check them out:

1. If you want to bomb a country every time an evil group murders people in a gruesome manner, you'll have to bomb a lot of countries including our own.  ISIS draws its strength in Iraq from resentment of the Iraqi government, which bombs its own cities using U.S. weapons, and which beheads people, albeit in grainier footage with lower production values.  Allies in the region, including allies that support ISIS, including allies armed by the United States (some of which arms end up in the hands of ISIS), themselves behead people regularly. But is that worse than other types of killing?