What do you think happens when they get one? They've just painted a target on themselves, and if you think they could just have a few nukes for protection, how would the countries in the immediate vicinity feel of Iran having nukes. They don't have the capabilities of hitting the west, but they will force the hand of the other global powers. Even China was ready to give up on North Korea when they became overly aggressive. Yes the US was the only country to use them, but thankfully they did decades ago before we perfected the technology. Only a few hundred thousand Japanese died to teach the world a lesson. The world learned that nuclear weapons were not weapons of war but weapons of annihilation. This is why they don't want more countries to get the nukes, because it doesn't level anything, it just helps bring about complete destruction.
Do you think that the US, Russia, China, UK, France, India, Pakistan, and Israel are responsible enough to possess nuclear weapons? IMHO, nuclear powers are hypocrites other wise they would all got rid of their nuclear weapons stockpile by now to make the world a bit safer.
And, who do you think that theses nuclear weapons are being pointed at?
If the US are spying and tramples on their own citizen rights, then they are capable of inciting hates and robs/steals from non US citizens. Errr, wait a minute, the US are not just capable of, they are doing it at the moment with Afghanistan, Iraq, Iran, Sudan, Libya, Egypt, Syria, and Israel (supporting the Zionists with weapons to attack Palestinians), among many other countries.
I'm not trying to justify that seeking or owning nuclear weapons is right. I'm implying that the genie is out of the bottle, and everyone are going to seek nuclear capability with or with out the US approvals. Case in point, Israel, North Korea, India, and Pakistan. And, I'm implying that it doesn't help the situation any because countries such as Iran feels threaten due to the fact that they are being surrounded by their enemies.