A destabilization of a nuclear power is against everyone's interests, the US included. I know the fad is to assume that the US has an evil hand in everything in the entire world, but honestly, I don't think anyone in power in the US's government wants terrorists with nukes. Also, if you haven't noticed, there are no indications that the US is going "OMG BROWN PEOPLE WITH NUKES". Lastly, I have not heard anything about the US and it's missile defense system, and honestly, they don't need an excuse to build it there - they don't have one now, this won't suddenly change everyone's minds.