Russia is more trustworthy than Iran. Nonetheless, nobody wants Russia to have nuclear weapons, but nobody can do anything about it. They've already have them for a long time.

I don't trust anyone with nuclear weapons. It would be lovely if nobody had them. That's realistically not possible right now. As long as countries continue to amass them, there's a need for "more good" countries to keep them. These are almost always democracies.

Democracy is generally speaking just safer and better than dictatorship. I'm just going to stop there, and not get into a debate right now of democracy vs dictatorship.

Would you rather have the good man with the power, or the bad man? That's the ultimate question simplified. You want the good man with the power, then it's a question of who is good, which would lead to huge endless debate right now.

If nobody had nuclear weapons the second world war would have lasted longer and the invasion of the Japanese mainland would have cost far more lives (on all sides) than the bombings of Hiroshima and Nagasaki did. The cold war would probably have gone hot, Europe would have been a battlefield and might have ended up under Soviet rule. As to how the conflict between China and the Soviet Union would have gone I can only speculate, that there would have been one is rather likely.

Nuclear weapons have kept the large powers from direct confrontation since the 50's, their existence has saved more lives than their use has cost. As long as they are not acquired by (in our eyes) irrational or suicidal actors they can be used for this purpose. As to whether a nuclear armed Iran would use them as a deterrent or otherwise - which includes providing nuclear weapons to third parties for use against common enemies - I can only guess. My guess is that a weakened theocracy - which is what Iran is - is an irrational actor and with that not to be trusted to "do the right thing".

> If nobody had nuclear weapons the second world war would have lasted longer and the invasion of the Japanese mainland would have cost far more lives

Yes, that's what we were told. But, was it really necessary to bomb Japanese cities to show them force?

Nagasaki was not necessary, Hiroshima ended the war. The war would have ended without it as well but the number of lives lost during an invasion would have been far greater than those lost during the bombings.