If only it would work like that graph...
First point, your graph assumes nukes are the all powerful weapons that kill everything, that is not true, they will cause a lot of suffering human death toll etc. But they are not so succesfull against objects, bunkers etc.
Second point that means the ''we retaliate, everybody dies'' claim isn't right either, everyone that can shelter can survive those who can receive treatment and are outside of the epicentre, will partly survive too.
Thirdly the biggest issue with nukes is their long term damage and the lack of knowledge thereoff yes we know what the bomb on Japan did but since lots has changed, so it isn't as clear cut.
I agree with you that in an ideal world we would have never made nuclear weapons, but we crossed that line, assuming that decommission them and hope that we don't have them is enough of an deterrent for evil regimes is foolish.
I also agree with on on the principle of the UN and security council, i just don't think every department of the UN is lead by thev right people(like the UNRWA for example)
The security council is indeed not really working but i don;t think removing the veto would change anything other then countries leaving the UN all together if they can't get their way.
