Iran Does Not Need the Nuclear Bomb
They have Al Qods brigades. These are the secret, special force-like forces that have been already planted in Saudi-Arabia, Kuwait, Turkey. These small cells contain people who look like others in that region, yet, these are highly trained and are awaiting a signal to conduct a terrorist attack.
While a nuclear bomb would bring world attention to Iran and new power, having these special forces, highly trained are much more under all radars and just as effective or can be. For example, Iran has blustered about not allowing US carriers back into the Persian Gulf and say they will close the Strait of Hormuz. Either one would be so provocative that it would demand a US response and escalation. If Iran's Al Qods cells simply blew up key oil pipelines, oil terminals and oil fields in Turkey, Saudi Arabia, Kuwait, Bahrain, the mayhem to the world's oil would be greatly damaged with far less human death and atrocity. The atrocity would be upon the local environment and the repair\clean up. This could be very effective, now , add Iranian anti-ship missiles or mines crippling even a few oil tankers passing through the Strait of Hormuz, suddenly, the combination of the two is very significant to the world and all this without much loss of human life.
The West would be frantic dealing with the in-country terrorist cells, dealing with the oil stoppage, cleanup and repair of destroyed oil fields\terminals or pipelines, dealing with a military response to Iranian missiles sinking 1 or 2 tankers and cleaning up the mess they create.
In a word, total havoc on the West's oil supply with very little loss to themselves. The West would be so busy with related issues simultaneously, that would, in effect, paralyze us for a short time. If the West attacked the nuclear sites, you just know the Al Qods cells in other countries will receive orders to activate and attack similar targets-heck with hotels, they would go for the oil jugular because the oil pipeline is unprotected for hundreds of miles.
That is why Iran does not a nuclear weapon. What is more scary is they think they do and want that international respect and status.