Muggaz, please refrain from painting all us Americans with the same brushstroke. We don't all hold America to different standards than the rest of the world. We don't all think that lashing out and attacking is/was the best response.
And to answer your question: I don't think that it is Pakistan's response that the world would need to fear, rather al Qaeda's. I can't pretend to think like them, so I can't tell you exactly what they would plot in response to this hypothetical attack, but I am sure it would be deadly.