I'm an American and am split on this topic, leaning towards the side of prevention of Iran's arms wants. If we, and a few other nations are allowed to have nuclear weapons, why shouldn't the rest of the world have the same right? At the same time though, what are their intentions of having nuclear weapons? Clearly to either (1) protect their homeland if need be - that's why the US has them/cold war fallout (2) act as alpha male in the region - not too stoked on Iran doing that (3) potentially use them.
I side a little closer with the ban on countries such as Iran gaining nuclear weapons - I just don't think the government has enough stability to prevent a terrible outcome, ie. using one. But who am I to say they can't have them, the US used them in Japan and it'd be hypocritical to say Iran can't have them. I'll bite my hypocracy though and believe that a country such as Iran has no foundation to harness nuclear weapons.