For its part America, enjoying merely the illusion of a unipolar moment in what is an increasingly multi-polar world, has interests in Asia not least of them steadying the now nuclear-tipped rivalry between India and Pakistan, and managing the rise of China where easier relations with India could help.
Meanwhile, what cause would be served by setting off a nuclear chain-reaction that would detonate a bomb under the disarmament progress so far, sour relations with China and provoke Pakistan then maybe Iran into going nuclear too?