As a sovereign country, yes, they have the same right to defend themselves as any other country. HOWEVER, they signed a treaty which said they wouldnt pursue them, so until they revoke it, they dont.
"It's always reassuring to find you've made the right enemies." -- William J. Donovan
Laws aren't worth the paper they're printed on if no one is going to enforce them. Guess what? Where the affairs of powerful nation states are concerned, no one does.
Frankly, I'd argue that any law which upholds the ability of nations like Iran or North Korea to produce weapons of mass destruction is flawed, and therefore should be ignored or worked around in any way possible.
“The reasonable man adapts himself to the world: the unreasonable one persists to adapt the world to himself.
Therefore all progress depends on the unreasonable man.” ― George Bernard Shaw, Man and Superman
I think it's naive for any person with the capacity to follow current events to "genuinely believe" that Iranians will forego what's apparently been an aggressive pursuit of building a formidable program until they get the blessings of the president and/or the congress. As you implied, they may already possess a higher degree of technology and even material.
North Korea at times would pretend that they hadn't advanced their efforts to have nukes. But then their psychosis would take over and jam it down the West's throats that they were nuke ready and armageddon was just around the corner.
If Obama, the military and members of Congress aren't pondering the possibility that the stage of Iran's program is advanced, then what verifiable intelligences would be available to them, which would alleviate their need to ponder - and choose to engage in some type of agreement? Obviously by the Republican's recent reaction with the open letter to Iran, I'm guessing that they aren't getting such intelligence.
But as the old saying goes, "A bird in hand is worth two in a bush." There's no second guessing about Pakistan's possession of numbers of nukes, which I don't think they've managed to keep an accurate accounting of. It's been said that not even Russia has an accurate inventory. That's freaky, in and of itself.
The theory that the U.S. Government has systematically been dumbing down the citizens for many decades has now been proven on November 8, 2016. In fact, not only proven, but quantified.
Reason i'm not worried is they are deterred by the same reality of MAD as every other nuclear regime since the cold war. Any statements to the contrary are most likely meant to appease the hard liners within and to convince the population the regime is needed. I don't see why the ayatollah is more of a suicidal war hawk than putin
This isn't about world peace, it's about America trying to ensure its dominance. We have more nukes than every other country combined, minus Russia, and we're the only nation on earth to use them against human beings. Where is our moral high ground?
"If I take death into my life, acknowledge it, and face it squarely, I will free myself from the anxiety of death and the pettiness of life - and only then will I be free to become myself." ~ Martin Heidegger
If Iran does get nukes I believe it will help stabilize the Middle east. No nation would attack another when both have nukes. MAD worked for us and the USSR and it should work for foes like Isreal and Iran.