We must avoid the horror of a future nuclear military encounter.
The WWII victors have nuclear weapons but have generally managed them wisely. Fortunately the world community has not used the arsenal which exists despite some 66 years and many severe top level arguments having arisen or been in the offing. It is a great achievement of restraint which spans the big cultural divide between the world nuclear powers.
Mutally Assured Destruction has sobered the powers into a reserved attitude.
The same might not be said of Islamist forces if they got hold of a nuclear bomb. This might specially be a danger if an Islamist-included sovereign state obtained one and a state having them became Islamist (as is a danger in Pakistan). Non state operators might be able to get hold of a bomb in that there are a lot around under inadequate security particularly if any nuclear power falls into poverty or disorder or regime change. More easy to obtain and less dangerous but still a serious hazard is the possibility of a non-government Islamist movement getting hold of nuclear material for a “Dirty bomb” which is technically much easier to operate.
It seems that Pakistan, India, North Korea and Israel have such bombs and now Iran is thought to be near to having some bombs.
Again this is a function that a properly functional UN can address itself to better than it is able to at present by the IAEA.
The antidote to all this is to have a world where there aren’t big grudges or if there are, where those with grudges are vastly outnumbered by people who are great about the fairness of the way the world is run in their day. Such people would tend to suppress or expose people of anti-social intent and if necessary to be prepared to put up with necessary security measures if they were people who have benefited from a benign world order and know they have something to lose if they don’t expose evil. So we had better get on with the job of making the world wholesome place where almost everyone wants it to succeed.