Look at it this way. A bunch of armed men are sitting in a circle with shotguns. There is no love lost amongst any of them. Would any one of them willingly give up their gun?
Of course nukes are weapons of mass destruction and would probably bring about the end of mankind blah blah blah, but seriously, what country would give up their ace in the hole just to stay on the moral high ground? Specially if the chances of everyone else giving up theirs are non existent....
Personally I think nukes are dangerous and if they ever fall into the hands of suicidal extremists that would be a really bad day. But until then no one who isn't suicidal will actually use one, just because they are so dangerous.
Also China and India follow a no first use doctrine, which many other NPT nations don't.
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