We should have a nuclear weapon (actually two) for each and every city and town within the domains of our enemy states... so that if anyone dares attack us with nukes, we could assure that such a nation ceases to exist as punishment for that crime...
The nukes remain a major factor that have prevented us from becoming another Iraq or Libya.
Iran understands this and maybe that's why they are aiming for nukes themselves (if they are planning on that at all).
But how is it that Pakistan's is on its way to number 4 so soon? Haven't they considered that other countries might also plan on expanding ?