What is to say Iran doesn't have the same duty to protect itself?
Sorry, you cannot decry Iran pursuing nuclear weapons, and in the same breath defend our possession of them, without being a hypocrit.
I certainly can. A nation is not a person.
I think we should have nuclear weapons to
protect our nation attack other nations that have attacked or are planning to attack us (a nuclear weapon is not a defensive arm.) I'm sure many Iranians think the same. However, I think the leaders of Iran are nuts and should not have those weapons, as do most of the people of this nation. (And most of Western Civilization, as well.)
We have the power to stop them from getting such weapons AND WE SHOULD DO SO. Nations don't have "rights".
As for your question about what happens if a stronger nation than the US decides we shouldn't have nuclear weapons. That's very simple. Should they be sufficiently stonger, they will take them from us or force us to give them up. If the US is no longer the dominant power in the world, we will return to the normal savage state of the world.