The Iranian situation is clear. If the Iranians had nuclear weapons, they would use them against Israel. This would cause a massive nuclear strike on Iran by the Israelis that would decimate the entire country. Both countries would be decimated, and the nuclear gynie would be out of the bottle.
This scenario could well bring in the US and Russia as nuclear adversaries in the dispute. Escalation to that level would be the end of the world as we know it — back to the dark ages.
This is why Iran cannot be allowed to have a nuclear weapons. They are crazy enough about the Israelis to use them.
Anyone who doesn’t understand all of this is either a fool or delusional, that is, living in lala land.