I'm not into politics but here are my 2 questions.
1. As far as Iran is concerned why are they not allowed to have nuclear weapons? Why can the USA have nuclear bombs and they may not? If I would be Iran I would say "before we start ANY deal, I want all you big guys to get rid of all your nuclear weapons. (of course WE know that Iran supports terrorism, still China and a lot of other countries consider Iran as a normal country, so here is my question)
Who said the US gets to decide who can and who cannot have nuclear weapons?
I'm not into politics either.
But the real answer is that there is treaty signed in1970, and in 1995, the Treaty was extended indefinitely. Its called the Non-Proliferation Treaty or NPT. A total of 191 states have joined the Treaty, though North Korea, announced its withdrawal in 2003. Four UN member states have never joined the NPT: India, Israel, Pakistan and South Sudan.
The treaty prohibits the members from developing any new nuclear weapons, but allows them to share nuclear technology.
Israel never signed, so its not bound by it, Iran signed. Most likely Israel had the bomb before 1970, so they are probably not in violation even if they had signed.
Oh, the treaty also talks about disarmament, but lets not get sidetracked.