Iran has a fundamental need for an alternative energy source, for many reasons. First and foremost, Iran must support a rapidly growing industrial sector and a demographic explosion. Second, its oil extraction infrastructures are, to my suprise, in tatter, and are barely able to meet international demand, so we cannot expect this oil rich country to use its own fuel to power its own economy and expending population. And thirdly, the only way for Iran to actualy make money out of its own oil is by selling it to foreigners, not by using it themselves.
So Iran is looking forward to a booming energy demand, and cannot use oil to supply itself. The only viable solution would be nuclear energy. That, or an economical recession and ensuing crippling poverty.
On the other hand, Iran does not have an inalienable right to nuclear energy. Tthe so-called right to nuclear technology and know-how found in Article IV of the Non-Proliferation Treaty, which Iran signed, is conditioned on a state behaving "in conformity with articles I and II" of the treaty - articles which prohibit activities that lead to nuclear weapons proliferation. Add to this fact that, during the negotiations over the NPT, specific proposals were rejected that would have made it a "duty" for weapon states to aid non-weapon states with nuclear technology transfers and know-how. The point is that Article IV should not be interpreted as giving non-weapon states a presumptive title to such transfers. The NPT is, after all, a treaty against proliferation, not for nuclear development.
Secondly, Iran kept its nuclear reserches secret and lied about it for 20 years. Coupled with its support and control of terrorist groups such as Hezbollah and probably others, we have every reasons to assume that Iran is gulty until proven otherwise. Western countries have no reasons to trust Iran one bit, and they are entierely justified in their suspicions and sanctions, and potential enforcement of those sanctions.
And I'd like to point out that States are not moral individuals, so moral rules such has "innocent until proven guilty" cannot apply to them. States have no duty to be generous, compationate, or to aby by any laws or rules whatsoever, unless they have something to gain. Scholars and intellectuals have tried for more than a century to try and determine the behavior of States, but they failed at it. The best that they came up with is the concept of State as rational actors. States are expected to act in their own interest, and if you want to predict the next move of a State, try and understand what are its interests.
In Iran's case, the 100$ question is, is it in its interest to develop nuclear weapons? Being aware of the new preemptive strike doctrine of the americans, knowing that they have a good shot at being a regional superpower in one of the world's most vital energical and cultural region, and having openly admited their goal of opposing western interests in the region (this include, among other things, our essential but questionable support to Israel's existence), and knowing that North Korea wasn't punished for its own nuclear developpment, I'd say that Iran will probably develop nuclear weapons.
Now, as I said, in inthernational relations, there is no place for moral question that concern only individuals. You cannot justify to me that we should assume that States are "innocent until proven guilty", because 1) we have good reasons to assum that Iran has no innocent purposes in mind for its nuclear energy and that 2) we have no reason to care if they are innocent anyway.
