>> well, one of the challenges taken some historical events, like the osheraq, iraq strike and possibly striking syria a couple years ago. they acted, they have resolved, they took care of the problem it went away. this is not a pinpoint -- single target, one strike and it's over. they've been pretty clever about distributing stuff. to really take care of the problem, when somebody decides they want to do it kinetically or militarily, it's going to require some people. and quite a few in the country which is not likely to happen. >> but -- >> you can do air strikes, delay things to cause them some havoc for debate. >> well, give me an example of -- have they got it spread out over a wide area, is it very deep? why is it such a hard thing to do? >> well, this is part of the calculus of red lines. but for a long time, most of their activity occurred at one site which was somewhat underground but certainly strikable. but they have over the past two or three years talked about alternative sites. we know of one that is pretty well understood, which is deep enough underground, there aren't we