Segnalo ai carissimi lettori quest'intervista a Mark Fitzpatrick, uno dei principali esperti internazionali in materia di proliferazione nucleare. Data la lunghezza originale ne ho estrapolato i punti salienti ma consiglio comunque di leggerla interamente.

What are Iran's nuclear capabilities?
There is no doubt that Iran is seeking a nuclear weapon's capability, and I think this is beyond reproach except from somebody who is ready to believe anything Iran says. Just based on the economic logic of their program, the military ties, the evidence of nuclear weapons development work, the lying, the hidden nature of it and so forth–everything points to a desire to be able to build nuclear weapons should they make the decision. I don't know that anyone can say that they have made a decision. I don't know that they've decided themselves whether to produce nuclear weapons, but they want to be close enough so that if when they make a decision, they can do it. And that's the threat.
The deliverability part of it is exacerbated by Iran's simultaneous pursuit of ballistic missiles that are capable of carrying a nuclear weapon if Iran can make it small enough. The development of Iran's program points toward being able to deliver a first generation 1 ton sized nuclear weapon at a distance that could easily hit Israel. They do not have a missile that today could deliver a nuclear weapon to Europe–and why would they it wouldn't make any sense. But certainly they would like to have what to their minds would be a deterrent capability vis-à-vis Israel; it would also be potentially useful to them to be able to threaten Gulf states.
What Iran possesses today and what they are developing seems to me clearly to be directed at Israel and other countries in their near neighborhood within 2200km. The Sejil is their most worrisome ballistic missile, it has a reach of 2000+–say 2200-2600km–that puts Israel squarely on the target by means of a missile that is deployed far enough back from Iran's borders that it wouldn't be susceptible to preemption.

Given what we know about Saddam Hussein's actual nuclear capabilities, how can we be sure that the Iranian regime isn't also bluffing and merely trying to look tough?
It's a good question; though it's an easy question to answer. In the case of Iran we have IAEA reports of inspectors. We know what its nuclear capabilities are. We know what their missile capabilities are–not on the basis of inspections, but on the basis of tests. It's all observable activity and nothing is presumed here about what the actual capability that they have.
The only presumption is the one that jumps from Iran's capability to the assessment that what they seek is a nuclear weapons capability; few analysts who would argue with that. The only argument would be about whether Iran has already made a decision to develop a nuclear weapon or not.
It's pretty clear that Iran until 2004 was engaged in weapons development work. Have they continued since? The British French and Israeli intelligence all think that they have. In 2007, the US NIE assessment argued that Iran had suspended their interest in developing a weapon, but that report is now being reassessed.

American and German neoconservatives and Iran-hawks (certainly a minority group in Germany, but increasingly vocal here too) argue that the Iranian regime is too ideological, irrational, and therefore unappeasable. Is this true?       
We need to distinguish between the argument about Iran's "irrationality" and its "unappeasability."
I certainly disagree that Iran is irrational. This is demonstrably false: When Iran has been faced with severe national trauma it has taken decisions that a rational country would take. In the case of the Iran-Iraq war, Iran accepted a ceasefire–they did this late and lost thousands of young men when they should have accepted it far earlier–finally because it was in their national interest. They may not behave like Western states, but there is a rationality to their actions–the desire to yield more influence and gain more prestige in the Middle East for example–that is not irrational. And finally, the most important reason that Iran cannot be considered irrational is that the decision making process in government is based on consensus. There is not one sole decision maker. Even if one man is deeply ideological or irrational; decisions are made based on consensus, which ultimately leads to rationality.

Is Iran appeasable?
Now, that's a different question and I'm not sure about the answer to that one. The question boils down to Iran's intentions: does it want a nuclear weapons capability more than anything else? And if so than no, they are not appeasable. No amount of sanctions or positive incentives will dissuade or stop a country that has decided to pursue capability or bust. Look at the case of Pakistan: their former president said that if India get's nuclear weapons, we'll pursue them even if we have to eat grass.
In Iran's case, I don't really see why they would feel the same; they don't have an India-like enemy. I don't know that they've decided that they want nuclear weapons above all else. Which is why we should try negotiating strategies that increase the benefits if they do suspend their program and enforce sanctions if they do not suspend it.

Some have argued that these are simply temporary rational compromises for a regime that wants to move toward ultimately irrational apocalyptic ends–like for example the destruction of Israel. What do you make of the leadership's calls to destroy Israel?
There is no evidence that the leadership is moving toward apocalyptic goals. To me that is so out of the realm of consciousness; it's just imaginations gone wild.
As for the goal of destroying Israel, I don't think this is Iran's goal. In Farsi, the meaning of Ahmadenijad's statements is that Israel would cease to exist as a Zionist State in the sense that Palestinian majority would vote within a state that would cease to be Jewish. That's what he means by this statement. I don't doubt that some Iranians would like to attack Israel, but they know that this would be a suicidal effort because of Israel's second strike capability. Many Neocons take it at face value that he means by force, but this is incorrect.

What is the objective of the most recent 4th round of UN sanctions?
None of the countries who have promoted sanctions think that they will change Iran's behavior.
There are 3 objectives to sanctions: First, to bring Iran back to the negotiating table in sincerity. Second, to restrict Iran's ability to acquire the wherewithal to expand their nuclear program. Unless they can acquire the materials and comp from overseas suppliers. They can't produce everything domestically. If their access to overseas supplies is limited, it's a way of keeping their program in bounds. Third, the broad purpose of heightening the downsides to their pursuit of capability. So that the Iranian people can see that there is a price to be paid. So that in future negotiations, you can withdraw those sanctions as incentive. And to show potential Iran wanabees that there is a price to be paid. That disincentive is crucial.

Are sanctions working?
They are certainly working for the second and third objectives. As for the first, it is too early to tell. Iran is talking about returning to the negotiating table, but it is not talking about it seriously enough yet. It hasn't agreed to any date or specific agenda. Catherin Ashton has been trying to get Iran back to the table and Iran has been signaling that maybe they'll be ready to do so soon. But again it's too early to tell. I'm hopeful that they may come back.

What happens if sanctions fail and Iran doesn't return to negotiate?
There are two broad categories of strategy: the first is one that I do not advocate and that's the strategy of military action to stop the program kinetically–

Ever?
No, I don't say "ever." There is a time and place for military action, when they cross the line between capability and production. Right now they have growing capability. If they were to test a nuclear weapon or to expel inspectors, or to produce weapons grade uranium, or to declare themselves a nuclear state (all things that North Korea did), well then yes, I think it would be grounds for attack to stop them from delivering a nuclear weapon.
A military strike is to my mind a potentially a lose-lose option. It probably would create conditions in Iran that would lead them to acquire a weapon for sure in possibly a shorter time than they would otherwise, because they would have the concerted effort of the nation and national economy toward this one goal of getting a nuclear weapon. And it is not a concerted effort today to go as fast as they can. If you look at the time it has taken them since they started this program in 1985–25 years–and they are still not there. Pakistan took about 10 years, but they had a concerted effort to get there. So if Iran were bombed today, it would set them back a few years, but then they would probably by hook or crook be determined to get it.
You'll set them back by a few years but give them a sense of national unity and an international excuse that much of the 3rd world would applaud: Iran was attacked so they have every right now to pursue nuclear weapons.

And the second strategy?
The second strategy is deterrence and containment: this is a tried and true strategy that has been proven effective for the West vis-à-vis the Soviet Union and China. They deterred those countries from ever using a nuclear weapon. They contained them from expanding their influence.
I think in this case, deterrence can work not only in preventing Iran from using a weapon but also from producing it. If Iran knows that the production of a nuclear weapon will result in a military attack, I think that could be an effective deterrent that would keep them on the capability side of the line (rather than actually producing it). As long as they don't cross that line to producing, it will be hard for Americans to condone another military action in the Middle East, but if Iran crosses the line, I think most Americans realize this would require military action. Willingness to use military force is absolutely necessary for deterrence to work.
Containment policies will keep the program limited. Sanctions and export controls are one form of containment, but there are others. Sabotage efforts to try to destroy or introduce imperfections in their equipment. This has been successful in the past and is one of the reasons Iran's program isn't working so well.

Are the US or Israel capable of a successful military attack?
Yes, absolutely. I think it's a good thing that Iran knows that a military option is a real option. I certainly think it is a real option. Iran glibly postures that the US is too overextended or that Israel doesn't have the capabilities for an attack. This is wrong. Israel does have the capability and the US would also be willing if necessary. The nature of the Iraq war has changed and the US is not nearly as extended as it was before.