Skip to main content

The Challenging Questions about the Iranian Nuclear Weapons Program

Max Singer

View PDF


The governments of Israel and of the US claim to be in agreement that Iran must be prevented from becoming a nuclear power, and that military action will be used for this purpose if necessary. They agree that military action must be taken before Iran has gone so far that an attack from the air could no longer prevent them from having nuclear weapons. And they agree that this point could come sooner for Israel than for the US, because Israel cannot make as large a military attack as the US can.

There are two critical questions which need more attention. First, if Israel attacks when the US believes there is still a chance to stop the Iranians without an attack, will the US join in international condemnation of Israel or will the US support Israel politically after the attack and use its deterrence to limit Iranian retaliation? Second, how far away from having nuclear weapons must Iran stop in order for Israel and the US to decide that they do not need to make an attack? In other words, what is the physical meaning of Iran becoming an unacceptable “nuclear power?”

What Does the US Do if Israel Attacks Despite US Opposition?

The answer to this question is clear, although perhaps surprising at first glance. For the reasons discussed below, if Israel attacks the Iranian nuclear program despite strong opposition from the US, after the attack the US must – in its own national interest – support Israel politically and use its deterrent power to limit Iranian retaliation. And the US needs to make its intention to do so clear in advance.

Now the US is taking the position that it is unacceptable for Iran to have nuclear weapons and that bombing Iran to prevent it from getting nuclear weapons is what the US intends to do if necessary. Therefore it would be a double-cross for the US not to blame Iran if Israel bombs its nuclear program.

Note that this potential dispute between Israel and the US is not necessarily about any conflict between US interests and Israeli interests. Both countries agree that they each have a strong interest in preventing Iran from becoming a nuclear power. While the US as well as Israel could expect to suffer costs and casualties as a result of an Israeli attack, the US would also benefit from that attack. Whether the Israeli attack would be a net benefit or harm to the US depends on whether the US judgment that further diplomacy could succeed in stopping the Iranian program on time was correct. If the US judgment that Iran could be stopped by diplomacy was correct the US would be better off if Israel didn’t attack. But if the US were wrong about that, or if something came up that prevented diplomatic success and prevented a US attack, the US would have gained from the Israeli attack it tried to prevent.

If the US acted consistently with the position it is taking now, and blamed the Israeli attack – which it had opposed – on the intransigence of the Iranian regime in defying international demands to stop their nuclear weapons program and on the Iranian government threats to “wipe Israel off the face of the Earth,” (threats which were in violation of the International Convention against Genocide and of the UN Charter) there is a good chance that a number of European countries would take a similar position, and of course no UN Security Council action against Israel would be possible. This would seriously change the situation facing the Iranian regime. Among other things it would greatly increase the danger the regime would face from its internal opposition. Because that opposition would know that the world was not supporting the revolutionary regime, and presumably stood ready to accept, if not support, a replacement regime. The US has a lot of respect among many Iranians; the mere fact that the US blamed the Revolutionary Regime for the attack, rather than Israel, would influence some Iranian opinion.

There is wide public support in Iran for the Iranian nuclear program, which claims not to be a weapons program. But as reported by Michael Ledeen, several recent polls indicate that a large majority of Iranians favor giving up efforts to get nuclear weapons in order to end the economic sanctions against Iran.

If the weapon production facilities are attacked Iranians will need to resolve conflicting impulses. On one side they are patriotic and support their country’s right to have a nuclear energy program. On the other side many of them are bitterly disillusioned by the regime and inclined to blame it for anything that goes wrong. Some who have turned against the regime will respond to an outside attack by rallying round the government. Others will take the attack, and the assertions by the US and other countries, as well as Israel, as evidence that the regime really had a nuclear weapons program, and thus was responsible for bringing the attacks down on the country.

A US policy of post-attack support for Israel would very likely reduce Iranian retaliation – against Israel as well as against the US and others. Perhaps more important it would increase the deterrence against the Iranian regime rebuilding its damaged nuclear weapons program. If the US and others gave political support to the attack the Iranians would have to expect that if they rebuilt they would be reattacked. Thus an attack that physically only produced a year or two delay in Iranian capability could result in stopping it permanently, which is the goal of the US.

These reasons for expecting the US to stand with Israel if Israel attacks the Iranian nuclear facilities are purely a matter of “realist” analysis of US national interest. They have nothing to do with the influence of Jewish or Christian Zionist voices in American politics. The internal political effects in the US are complex, and would be different at different times through the rest of 2012.

For Israel a strike against the Iranian program would be much less dangerous if it knew that the US would stand with it the next day, because Iranian retaliation would be more deterred if the US and other countries were with Israel. Also an Israeli attack which caused only limited damage would be more valuable because it would have a greater chance of indirectly stopping the Iranian program forever.

A US statement of intent to support Israel if it attacked the Iranian program despite US opposition would also means that Iran would take the possibility of an Israeli strike more seriously. This would improve the chances that diplomacy could work, preventing the need for the strike.

Furthermore, Israel would have more reason to rely on the US to prevent Iran from becoming a nuclear power if the US promised to support Israel after an Israeli strike that the US had tried to stop. On the other hand, the case the US is trying to make to Israel now, that the US is absolutely committed to preventing an Iranian nuclear bomb, by force if necessary, is decisively undermined if the US hints that if Israel acts before the US thinks it is necessary the US will condemn Israel and leave it to face Iranian retaliation without support from the countries like the US that will benefit from the Israeli strike. How could Israel rely on the US to attack Iran if necessary if the US seemed to be prepared to condemn Israel for doing what the US said it was ready to do itself?

So the effect on Israeli calculations of a US promise to support Israel after an unapproved strike goes in both directions. On the one hand, such a US promise reduces the danger to Israel from Iranian reactions and increases the chance that it will lead to permanently preventing an Iranian nuclear weapon. On the other hand, such a promise increases Israel’s reason to believe that it can rely on the US to prevent an Iranian bomb if Israel refrains from striking.

So far there is no public evidence that the US has addressed the question of what position the US would take the day after an unapproved Israeli strike. This appears to be a serious gap in the mutual policy making about Iran.

What is the Meaning of “Preventing Iran from Having Nuclear Weapons?”

The question of possible Iranian stopping points on the road to a force of nuclear weapons is usually treated – by those who are not “soft” on Iran – as a matter of clever Iranian efforts to reduce the pressure it faces while secretly continuing to acquire nuclear weapons. But a genuine “stopping point” which both sides intend and expect to continue indefinitely (years and years) would be – if it happened — a different matter. For Iran such a stopping point might be adopted as their chosen goal, either for internal reasons or because they become convinced that going further would be made too costly or dangerous for them. For Israel and the US some such stopping point has to be the real goal of our military threats. We are trying to get them to do something. What is it? While we would like them to The question of possible Iranian stopping points on the road to a force of nuclear weapons is usually treated – by those who are not “soft” on Iran – as a matter of clever Iranian efforts to reduce the pressure it faces while secretly continuing to acquire nuclear weapons. But a genuine “stopping point” which both sides intend and expect to continue indefinitely (years and years) would be – if it happened — a different matter. For Iran such a stopping point might be adopted as their chosen goal, either for internal reasons or because they become convinced that going further would be made too costly or dangerous for them. For Israel and the US some such stopping point has to be the real goal of our military threats. We are trying to get them to do something. What is it? While we would like them to

Sometimes we talk as if our goal is for Iran to stop their continued advance toward getting a force of deliverable nuclear warheads, but as they get closer and closer we have to decide when simply stopping in place is no longer good enough.

In thinking about the political effect of “how far away is Iran from becoming a nuclear power?’ we usually have in mind a case where Iran is still moving forward and the question is a matter how long it will take to achieve their goal. But the question is different when the understanding is that the Iranian regime has chosen a stopping place. That is, they are, say, “six months from having nuclear weapons,” but they expect to continue to be six months away a year from now. Does that make them a “nuclear power” or doesn’t it? Would Turkey or Saudi Arabia feel compelled to match such an Iranian position? Or would they conclude that the Iranian case shows that additional Middle Eastern nuclear powers are not acceptable now?

Currently most discussion of limits on Iranian programs is based on the assumption that the Iranian regime is and will continue to try to build a ready force of deliverable nuclear weapons, and the problem is how inspection can overcome their deceit. But even if this is true today, there are two reasons we need to consider the question of what “stopping place” would be acceptable to us. The Iranian regime may decide to stop well short of what they have apparently been working toward, either for internal reasons or because of outside deterrence and pressure. And then we would have to decide whether to be satisfied. And, second, we have to formulate our demand to them. “We will attack your nuclear weapon building facilities unless you immediately do “ what?”

Israel has an easier problem. It would probably attack without an ultimatum. And its goal, with its limited capability, would be to cause as much harm to the Iranian program as possible.

Unfortunately, clear thinking about the meaning of an Iranian “stopping point” can be politically expensive. Definition of the stopping point is the subject of bargaining. Obviously we would like them to be as far away from a bomb as possible. They might like to be closer. But how much further away are we willing to go to war to push them? Putting it that way is what tempts them to try to go further, even if they have accepted the need to stop short of their original goal. And the whole discussion can tend to increase the ability of Ahmadinejad to use deceitful negotiations to gain time.

If the US attacks it is likely to try to destroy as much of the Iranian capability as possible, more than the regime would have to shut down to prevent the attack. If it is going to attack the nuclear facilities the US might decide to also attack the security forces now protecting the Iranian regime from popular resistance, and do other things designed to bring about regime change. Although the US might instead decide that stopping the nuclear weapons program without trying to remove the revolutionary regime was a less dangerous plan.

If the Iranian regime believes that the US will attack if it is not satisfied, then their interest is to give us the minimum necessary so that we don’t attack. But how much do they have to give? The more we discuss what would satisfy us, the easier we make it for them to answer that question. Perhaps fortunately they are not very good at evaluating our policy process. They may switch from confidence that we will never attack to some wild misjudgment of what is required to satisfy us. But it is also possible that they may be very clever in manipulating us to accept more than we have to. And quite possibly they do not believe that the US would ever attack.

It is also possible that they would prefer that the US or Israel attacks them rather than voluntarily giving up the goal of building a force of deliverable Iranian nuclear weapons. If that is true the question of a stopping point is irrelevant, as are threats of an attack – we are faced with a choice between an Iran with deployed nuclear weapons or an attack that prevents them from doing so.

There is a lot of unrealistic talk about internal opposition to the regime in Iran, and about the regime’s potential willingness to make a grand bargain with the US and to give up its nuclear weapons program. The discussion here has no connection with all that uninformed projection of Western desires. The assumption here is that Khamenei has controlled the regime without serious challenge by “liberal” forces such as Khatami, and that he sees the US as permanently the enemy of his revolution. Although some believe that Khamenei is constrained by Jaffari and the Republican Guard. And Michael Ledeen in his Pajama Media blog of July 9th reports that Khamenei has not made any public appearances in the last several weeks – missing several traditional appearances.

There are two kinds of “opposition” in Iran. First a large part of the population, perhaps a majority, would like to end the regime of the ayatollahs, but the regime has been able to suppress this opposition by police state measures backed up by the Revolutionary Guard Force, and some of the military. Second, among the powerful people and organizations who are within the regime, and who fully support its continuation, there are normal disagreements about policy issues and struggles for influence. While Khamenei has the final say, practical considerations require him to take into account the ideas of some of his loyal supporters – which is to say the balance of forces among the centers of power.

While it is very difficult for outsiders to have much confidence in the little that is known about the internal differences among elements of the regime’s leadership, it is plausible that there are important elements that prefer that Iran not go so far with its nuclear weapons program that it actually produces an operational nuclear force. Among other things, it seems likely that the existence of ready nuclear weapons, which would have to be held by some particular organization, would influence the internal balance of power. There would be gainers and losers.

Furthermore, if there are nuclear weapons they have to be protected against accidents as well as against theft – a whole new task and concern.

As Prof. Bernard Lewis has emphasized, there are elements in the Iranian regime who are tempted by the idea that if Iran was in a nuclear war the vast destruction would speed the return of the 12th Imam. But it is very likely that there are others who are frightened by this possibility, and they will understand that the most reliable way to make sure that it doesn’t happen is to not produce a set of usable weapons. Iran gets significant benefits from demonstrating that it has defied the world and produced what is necessary to be able to produce nuclear weapons in a very short time — unlike any other Muslim country except Pakistan. Maybe significant Iranian actors believe that that is as far as it is prudent to go. The intensity of the Iranian effort to get nuclear weapons up to now doesn’t answer the question of how far they will decide to go.

It is possible that the decision that would come from the conflict of different groups within the regime would be not to take the final steps of producing actual nuclear weapons. The terms of any internal debate would change if a large part of the regime became convinced that Israel or the US would attack the nuclear facilities if Iran were to produce ready nuclear weapons. While some would not be deterred by this danger, it seems likely that others, perhaps enough to make a winning coalition, would conclude that it was better for Iran to have a nuclear program that is capable of producing nuclear weapons but doesn’t actually do so, than it would to have an American (or an Israeli) military attack.

Because of its history of lies and concealment of its nuclear program up to now, if the Iranian regime decided to stop short of actual weapons in order to prevent an attack, they would have a hard time to convince the US and Israel that this was their decision and that they were not planning to secretly produce weapons. And they would have to say what “not having nuclear weapons” means to them.

Nuclear weapons are complicated machines with a number of critical parts. If any critical part is not there what exists is not a nuclear weapon; it can’t be exploded. But if the critical part is available, and can be added to what exists, it could be said that there are actual (unassembled) nuclear weapons. But suppose some critical parts have not been produced, although the tools and material needed to produce them are ready. If so there really aren’t any nuclear weapons, but there is the ability to produce them very quickly. But we are not likely to accept the idea that such a fine distinction meets our concerns. We probably would expect more reality to the claim that Iran had stopped short of producing nuclear weapons than the alleged fact that one or a few necessary components had not been produced – but could be produced quickly. But what condition of the Iranian nuclear program would meet our need that Iran “not have nuclear weapons?”

In principle we have to ask ourselves what Iranian reality would be acceptable, as a separate question from whether we could be sure that they are really doing what they say they are. This has nothing to do with trusting Iran. If we decide to attack their program if it goes too far toward acquiring nuclear weapons we have to decide what is “too far.” And if they decide to stop partly to prevent us from attacking, they have the problem of how to convince us that they have stopped at that point. Although, particularly after our Iraq experience, we will be reluctant to attack if there are doubts about what the Iranians are really doing.

From our point of view, we are twisting their arms until they say, “OK we’ll do what you demand, what is your demand?” We have to have a demand which includes what we need to assure ourselves that they are doing what they say. The harder they make it for us to assure ourselves the greater our demand has to be.

This argument doesn’t depend on the idea that the Iranian regime is now doing anything other than going as fast as it can to get nuclear weapons, using “diplomacy” to prevent or delay US action against them, routinely using lies and false promises. If we are using diplomacy and threats to stop them we need to know what “stop them” means. If we think that stopping them is impossible we should attack right away.

There are two elements of nuclear weapons. The special nuclear material – plutonium or enriched uranium – and the components used to make this material explode. It is much more difficult and expensive to make the nuclear material than to make the other components of the bomb that uses the material. But there can be no weapon unless both are done.

Some of the considerations are:

  1. Has a bomb been designed and the components built and tested?
  2. Is it just a crude bomb made for testing or is it a weapon that could be delivered by a missile? (Although even a crude bomb could be delivered clandestinely, especially to a country like the Gulf States.)
  3. How much more time is required to produce enough special nuclear material for 2 bombs, or ten bombs, or 50 bombs?

One of the key questions is, how far does Iran need to go before it is treated as a nuclear power by the other states of the region? In a crisis situation, in which Iran is trying to prevent a country from resisting some action that Iran or a proxy is taking, the other country is likely not to treat Iran as a nuclear power if it is not thought to have actual nuclear weapons. But countries such as the Gulf states, who have to decide whether to be aligned for their long-term protection with the US or with Iran, may make judgments based on their expectation for the future. If they see that Iran is capable of producing a number of nuclear weapons in a few months – because they have the nuclear material and have developed and produced the other components of nuclear weapons – they may decide that long-term safety depends on accepting Iranian domination, because soon the US would no longer be able to protect them from Iran. However, perhaps they would react differently if Iran is understood to have stopped moving forward toward getting actual weapons, that is, because of either internal considerations or fears of outside reactions, it has deliberately stopped short of acquiring actual nuclear weapons. How much of a nuclear power is a country that has the ability to produce nuclear weapons in 6 months to a year, but is not moving to do so, and has in effect announced that it does not intend to do so, and in the meantime has no nuclear weapons?

So there are two different kinds of fears that set the definition of when Iran becomes a nuclear power. One is the fear that they could produce useable weapons too quickly to be stopped, and then be able to use them, sooner or later. The other is the fear that politically Iran will be treated like a nuclear power even if it has not manufactured any actual weapons. To respond to these fears the Iranian program must be attacked or limited by agreement before it produces the non-nuclear components of nuclear weapons or before its enrichment capacity is enough to change the partially enriched nuclear material that it has into enough fully enriched material for 5 or 10 weapons in a few months.

Unfortunately it is difficult to rely on intelligence about the design and production of non-nuclear components, because these activities can be done in small facilities with limited numbers of people. And it is difficult to know whether the Iranians would rely on untested weapon designs. Nuclear weapon technology is now nearly 70 years old, and generally available modern science and technology makes it much easier to produce nuclear weapons than it was originally, but it still is not high school and workshop technology, especially for a weapon that can be delivered by missiles.

One plausible stopping point for the Iranian regime would be before manufacturing multiple copies of the non-nuclear bomb components, and before machining the nuclear material into the shapes required for the weapon. That is, after developing prototype components and checking the assembly and the process for machining the nuclear material (and perhaps testing an experimental explosive device). This point has the advantage to Iran that it would permit continued development of the weapon design without having to throw away or convert the components from early generation designs.

If the Iranians stopped at this point they would not have any nuclear weapons that could be stolen or used right away. They would, if they had planned correctly, be able to manufacture perhaps dozens of weapons in something like six months if they had done a good job preparing the manufacturing equipment. (Probably the time would vary depending on whether they had recently adopted an improved weapon design.)

The other component of possible stopping points is the manufacture of special nuclear material. Bombs use uranium U235 enriched to some 90%1. Most civilian uses of uranium only require enrichment to a few . The Iranians could stop when they have a large quantity of uranium enriched to, say, 20, plus a very small amount fully enriched for experimenting and testing. It takes much more enrichment work to go from natural uranium to 20% enriched than it does to go from 20% to 93%. If they had enough 20% enriched uranium for 30 bombs they could produce weapons after the time it takes to enrich from 20% to 93%, which with the number of centrifuges they have built would not take very long.

If the Iranians decided to stop at this point, call it “pre-bomb,” they would need to decide what they wanted people to believe about their program. They might want to convince people that they had stopped well short of building nuclear weapons, undercutting the justification for attacking their facilities. Or they might want other countries to fear that they actually had weapons ready to use. (Given the inclination to conspiracy thinking in the region, they might be able to get both or neither.)

How could Israel and the US be confident that Iran had stopped at the “prebomb” point defined in this way? Outsiders would have to decide which of three possibilities was true. Iran, as it might claim, could be six or more months away from actually having a bunch of weapons, because they had a lot of manufacturing that had to be done before weapons could be produced – as well as a serious amount of enrichment work. Or they might have concealed weapons. Or they might be something like a month away from having actual weapons because they had secretly done the necessary manufacturing and enrichment but had not assembled any weapons.

Perhaps the only way the Iranians could convince the US and Israel that it had stopped at this “pre-bomb” point would be to let us understand their program. That is, they could show us their design and prototype manufacturing facilities, and also their standby manufacturing and assembly equipment, so that we could see what they were doing (although we might not have to know what their design was). Then the only question would be whether they also had duplicate facilities operating covertly. It might be harder to show us how much enrichment they had done. They could either provide this information to inspectors of some kind, or they could arrange so that our intelligence could learn the facts by our own clandestine methods, avoiding having to seem as if they were accepting our authority or power. We could be fooled, but if they wanted to, they could arrange so that it would be quite unlikely that we were being fooled.

This definition of a “pre-bomb” stopping place may be the optimum strategy for Iran. If the US and Israel were convinced that Iran really was, and intended to continue indefinitely to be, “pre-bomb,” and that we could effectively monitor their actions so that we would know promptly if they were moving beyond this position, neither of us would be likely to make a military attack on the Iranian facilities. On the other hand, politically Iran would get a significant part of the benefits of being a “nuclear power,” especially if they had tested an experimental, non-weaponized bomb. They might be satisfied with the extent to which they had accomplished what is required by their national pride and achieved a symbolic victory over those who tried to prevent them from becoming a nuclear power.

Of course other definitions of “a pre-bomb stopping place” are also possible – either closer to, or further away from, actual deployable weapons.

On the other hand, if the Iranian regime is working toward nuclear weapons in order to get the kind of protection from attack that N. Korea has achieved, then such a stopping point would not achieve their goal. And, since at least part of the regime has ambitious goals of weakening and defeating the US, they may well think they need such deterrence against a US attack.


It is clear that if Israel attacks the Iranian nuclear program despite clear and strong opposition from the US, it will be in the US national interest to condemn Iran and support Israel and use its deterrence to limit Iranian retaliation and prevent it from rebuilding their program. And it is in the US national interest for the US to say in advance that this is its intention.

It is unclear what “stopping point” in the Iranian nuclear program the US and Israel will fight to achieve. They agree that a military attack is better than allowing Iran to have nuclear weapons. But they have not decided what “not having nuclear weapons” means. And, while it is clear that Iran has been working to build the capacity to produce nuclear weapons, it is not clear yet how far toward producing an actual nuclear weapon force Iran will decide to go. Although until there is good evidence to the contrary the US and Israel have to assume that they intend to go all the way.

1 Nuclear weapons can also be made with plutonium, which is produced in  nuclear reactors.  But it is generally thought that Iran is further advanced in  producing enriched uranium than in producing (and separating) plutonium. 
View PDF

Related Articles

The Trump Peace Plan – Aiming Not to Make a Deal, but to Make a Deal Possible

Lewis Libby & Douglas J. Feith

The Trump peace plan tells the Palestinians that the sensible question is not whether a deal provides everything you think you are entitled to, but wh...

Continue Reading

Europe Frets, America Yawns: The Trans-Atlantic Gap on Domestic Islamism

Lorenzo Vidino

In April 2019, in a landmark speech, French President Emmanuel Macron sought to sooth the societal tensions laid bare by the __gilets jaunes__ movemen...

Continue Reading

How the Iranian Revolution Inspired Turkish Islamism

Svante E. Cornell & M. K. Kaya

The Iranian Islamic revolution of 1979 had important implications throughout the Islamic world, and Turkey has been no exception....

Continue Reading