If they can coordinate a half dozen or more nuclear explosions around the US, killing millions and devastating the country, it will facilitate Islam's takeover of the entire world. We're the Great Satan. Once we're shown to be impotent and weak, the rest of the western world will cave so fast your head will spin.
Like I said, they aren't rational if they think killing millions of Americans is going to help their cause. Even I'm afraid what such an attack will precipitate as our response. May cooler heads prevail for an approach that doesn't turn us into the same monsters who will have attacked us, but let those heads be determined and unwavering in seeking out justice for the dead.