It's not about "authorized" or "unauthorized". If Switzerland or Brazil acquired nuclear weapons, I don't think anyone would really mind. The problem is with religious extremists sponsoring terrorism getting nukes.
There was a hope that once they acquired nuclear weapons, rogue countries would become responsible, because they didn't need to worry about their own existence. Pakistan has proven this theory wrong, sponsoring terrorism in in its neighbouring countries and abroad while being immune from the consequences.
What marks a state out as being religiously extreme? Or sponsoring terror? Stuff like killing politicians of the opposing side? Pardoning insurrectionists on your side? Sponsoring organisations that badger mothers in foreign nations as they attempt to get an abortion?
> If Switzerland or Brazil acquired nuclear weapons, I don't think anyone would really mind.
I think all current nuclear-weapon states would very much care, because it diminishes their status. Also Switzerland or Brasil would be breaking the Non-Proliferation Treaty which would make even more countries and the UN and IAEA care.
There was a hope that once they acquired nuclear weapons, rogue countries would become responsible, because they didn't need to worry about their own existence. Pakistan has proven this theory wrong, sponsoring terrorism in in its neighbouring countries and abroad while being immune from the consequences.