Dave, if it were just us versus the Pakis, your solution would probably work. Even if it were just us and our allies versus Pakistan it would probably work. However, we have Russia and China with nuclear weapons who are definitely adversarial to our interests and France, whose people like us, mostly, (except for their Muslim population and a few jerks in government in Paris) but will push a stick in our spokes just because they can. Any attempt to retaliate with nuclear weapons against a covert strike on us or our interests would bring us to verge of a nuclear confrontation in an arena in which, thanks to BHO, ODL, (MHNBSUE) we no longer have a strategic advantage.
I think if there were a nuclear strike on the US, we would have a lot of latitude in our retaliation from the rest of the nuclear club. As for the Lilliputians in the UN General Assembly, do we really care what they have to say, particularly if we were the target of nuclear weapons.?
Russia and China in particular are as vulnerable as we are, and you can bet that neither would hesitate to retaliate if they were attacked.
Re allies, our allies are only as strong as their perceived interest in supporting the US. History is full of broken or abrogated alliances. Ask the Poles, for instance, about their pre-war alliances with France and Britain.
Where national survival is concerned, we would be fools to trust any other nation to have our sixes.
Or to think that today's adversary could never have common cause with us in a future conflict.
Alliances aren't marriages, they are expedient associations of convenience.