I guess it depends on what you mean by "What would YOU do?" If I'm me I wouldn't be doing anything much of what I wanted to do. I'd probably be pulled out of Afghanistan and deployed somewhere else. If the question is asked in the context of what I would do if I was calling the shots? The US response would dwarf that of any action we've ever taken in the history of our nation. The response would be so that no one would ever think it was a good idea to pull something like this, again, ever.