This is an opinion piece written by guest writer, Jeff Lefkowitz. Mr. Lefkowitz runs a history program in Houston, Texas and has studied the deal from all angles. His views stem from a deep understanding of Jewish and American history and volunteered to write this detailed explanation as to why he opposes the Iran nuclear deal.

Photograph: Martial Trezzini/AP

The essence of the disagreement over the Iran deal cannot be stated publicly by President Obama if he is to prevail in his battle for public opinion. This is because the ultimate issue is that President Obama and Secretary Kerry fear the consequences of a military strike on Iran more than they fear a nuclear Iran. They have made this clear through Obama’s acknowledgment that in 15 years Iran will have zero breakout time, and by Kerry’s references to Iranian threats against the United States and Israel as rhetorical excess. This is the true divide between the left on the one hand and the center and right on the other on the Iran question. The left would rather face a nuclear Iran in 15 years (with the hope that the future Iran will be nonthreatening)  than truly threaten or use American power now to prevent such an eventuality.

We should be much more afraid of a nuclear Iran in 15 years than of the ramifications of a military strike and even war against Iran now. This is clear  from the viewpoint of the US, not Israel. For Israel, the calculation is simple. You are a country of about 8 million in a small area with major population centers along a narrow strip. A dictatorship has spent much effort and money attacking you through proxies and announced it wants you destroyed. You see their having nuclear weapons as an existential threat.

Now from the US viewpoint –during negotiations.. Let’s go back in time a year or six months, before the announcement of a deal.

First, the key background: who is the Iran that we are dealing with? Who is this country that the US, other western counties and even Russia and China, to a degree, united for a few years to demand that Iran must not become a nuclear power, must not be allowed to enrich uranium, must shut down their facilities, and must not be allowed to have ICBMs? It is not the modern, western looking minority that we would like to be in charge. It is a dictatorship under the control of the “Supreme leader” and his group, supported by the Revolutionary Guards and the usual enforcement organs that go with dictatorships. To make it easy, I will refer to the leadership of Iran and their supporters as the “group”. Who is the Supreme leader? He looks like Santa Claus. He controls about 95 billion (yes billion, not million ) dollars worth of assets in Iran. Stolen from Iranians, members of minorities and others. (In other words, like most dictators, he is not a nice guy and you would not want to buy a used car from him).

What is the ideology that drives the group? We hear in the US a lot about the Shiite-Sunni divide, with Iran being Shiite and Saudi Arabia being Sunni, and there certainly is a lot to that and to the extremist religious views of a sizable portion of the group. But there is something more important : old fashioned nationalism and the desire to be great again as in the olden days. In this case, the days of the Persian Empire. The desire to once again control the middle east, as during the days of Darius, and to show the inferior Arabs who is great and who is weak. They do not simply talk about these things. They have propped up Assad in Syria as he massacred more than a hundred thousand of his people (before Isis was a household name) support Hezbollah, etc, support the rebels in Yemen, etc. Internally, Iran acts as you would expect a dictatorship to act, with the added spice of their Islamic fundamentalism. You do not want to be a Bahai or a homosexual in Iran. Iran is number one in the world in the number of known executions per capita.

The point is that although it is tough to pigeonhole them, the Iran that exists today is close to an old fashioned right wing nationalistic dictatorship with aspirations of grandeur(with religious extremism tossed in). Analogies are almost always misleading but there are reminders of pre WWII Japan or Italy (with obvious differences). The bottom line is that they are bad guys who want to exert influence and perhaps subjugate their Arab neighbors (think world oil supply). Israel has had nuclear weapons for years but you never heard Saudi Arabia say that they therefore need them. But the Saudis and other Arabs say that if Iran gets nuclear weapons they must get them as well — to counter the threat from Iran.

With that background, let’s turn to what the US should do in the negotiations, starting at the point that Iran announces that if Iran does this deal it must have the things that this deal gives it — the ability to have zero breakout time in about 15 years, the ability to enrich uranium, to get ICBMs etc, as allowed in stages over the next few years. (I am not going to address whether Iran could cheat and have secret facilities, whether the inspection regime is good enough etc, because my focus is on the fact that without cheating Iran will be a nuclear threshold state after 15 years, which is where we started this discussion) So given Iran’s demands, the US was faced with the following question: We are unable to get Iran to move on these issues, it appears that continued sanctions will not get them to move, so what if we said to Iran: “if you do not agree to our proposal (more on that later) we will launch air strikes and destroy all of your facilities. We will not attack anywhere else or seek to harm the regime. If you then respond militarily , we will respond as we see fit.” ? This requires the analysis of the central question: which is worse: military strikes now and the risk of full blown war against Iran or Iran with nuclear weapons in 15 years?

Actually, the appropriate first question is what is the risk of telling Iran, with the intent to follow through, that they must agree to our terms or else we will destroy their nuclear facilities? (The terms, incidentally that would be given to Iran in this “or else” scenario would be very favorable to Iran. They must destroy all of their nuclear facilities and stop all work on uranium enrichment, etc, but we would pay for and give them whatever they would need to develop a nuclear program for civilian purposes to the full extent that an oil rich nation would reasonably want that, they would not be required to stop any of their support for Assad and terrorist groups, sanctions would be lifted immediately upon the destruction of their nuclear facilities, we could even pay them cash, they could announce to their people that we caved in and that they did not really give anything up because they never wanted to develop nuclear weapons anyway, etc)

If we gave them this ultimatum in the secret negotiations, coupled with the favorable terms, what would Iran have done? The odds are decent that they would have accepted them, there would be no war, and there would be no Iranian nuclear program.

But of course, the Iranians may have rejected the ultimatum, either because they would see it as a bluff, or they are irrational, or their real goal is to get nuclear weapons, or other or a combination of reasons. So what would likely happen if Iran rejected it and the US then attacked and destroyed the nuclear facilities from the air? (We have the ability to do that, even as to the “peaceful” program under the mountain). What would Iran do in response? That is unclear, so lets analyze it. When Israel destroyed the Iraqi nuclear reactor in 1981, it did not lead to war. When Israel destroyed the Syrian reactor (being built with North Korean help) in 2007, it did not lead to war. Does that mean that an attack on Iran would not lead to war? No. But it is certainly evidence that the attack by the air to wipe out the nuclear facilities is not equivalent to and may not result in war. Why did eliminating the nuclear sites in 81 and 07 not lead to war? Because the Syrians (even with their Iranian backers) and the Iraqis knew that they would lose if they responded militarily. The Iranians would know this also with an immeasurably greater imbalance between them and the US now as compared to a war of either Iraq or Syria then vs. Israel. The odds are good that Iran would not have responded militarily against the US if the US destroyed their nuclear sites from the air.

But I could be wrong. The Iranians may respond irrationally or for other reasons. How would they respond? First, let’s put their military in context with that of the US. It is dwarf vs giant in terms of conventional warfare. Iran fought Iraq to a standstill for 8 years. The US defeated Iraq militarily in a few weeks. (I am not referring to the ensuing debacle , the wisdom of the war, etc. I am simply citing that as an example of the relative military strengths). The Iranians know this, which relates to whether they would attack the US in response, mentioned above. But I will get back on track: how would the Iranians likely respond if they did respond militarily? Their options against the US include attacking the US fleet, trying to block the shipping lanes, attacking US military bases in the area, unleashing suicide missions on US soil, a combination of the above. Worst case, if they did all of the above, we would have a full-fledged war with Iran. The results militarily would be similar to the military results of the Iraq war. The post war might be significantly different from the Iraq experience because of the large number of ethnic Persians in comparison to the remainder of the population, but that could be off base and we could end up with the same sort of civil war as has occurred in Iraq. The bottom line is that the result of war would be bad. A couple or few thousand American boys would be killed and larger numbers of Iranians would be killed in the war. (Among the casualties would likely be many Israelis because Iran would likely cause Hezbollah and Hamas to rain missiles on Israeli civilians and Iran might also attack Israeli directly with their own missiles). It is even possible that Iran might respond to an American attack on their nuclear sites by only attacking Israel and not the US, which would cause great destruction in Israel, but not the US, and our focus here is on the US. (Worse case for the US is it would lead to the war between the US and Iran mentioned above)

What would be the response in the region to the US attack from the air on Iran? Assad would be very unhappy. The Saudis and the leaders of the major Arab powers would be happy. Many of the disgruntled and “on the fence” populations in those areas would see it as another example of American imperialism. On balance although the common person who fears Iran would be happy, it would feed into the anti-Americanism and belief that the US is bad. That would be a bad consequence. But it would be far outweighed by the fact that Iran would no longer have nuclear weapons capability. (The comments by Kerry that it would be ineffective because Iranians would still have the knowledge in their heads is beyond absurd as their practical ability would be gone). A positive effect is that other bad guys in the region would get the strong message that they will not be allowed to develop nuclear weapons. This is very important.

Before I address the risk of a nuclear Iran in 15 years, I will address a couple possible side effects between now and then. First, it may lead to war, between now and then, as the result of Israeli acts to prevent Iran from acquiring nuclear weapons. What Israel might do and and the consequences are unknown, but there is a risk. (Incidentally, if Iran were caught cheating say, five years from now and the US decided to strike from the air, we would face Russian made surface to air missiles that Russia has promised to furnish and Iran may get next year).

Secondly, the odds are good that the Saudis, maybe Gulf states and Egyptians and/or other Arab dictatorships in the region may elect to acquire nuclear weapons, as some have threatened. This would lead to the possibility that one or more of them may lose control of their weapons if/when their current governments are overthrown, with the risk that the nuclear weapons would fall into the hands of non state actors (terrorist groups). Prior to this agreement, these countries have been aware that they would be prevented by Israel and maybe by the US from becoming nuclear states. This fact would certainly have been reinforced if the US prevented Iran from doing so. That dissipates as the result of this deal. This is a very important negative consequence of the agreement.

Now I will turn to the risk of a nuclear Iran in 15 years. (The choice of 15 is not exact – they could cheat and have them earlier. But it is undisputed that under this deal they would be a nuclear threshold state within 15 years, as Obama alluded to in his interview when he said the breakout time would be zero — I am using 15 as a reasonable plug number).

The first question is who will Iran be in 15 years? The dictatorship/group as exists now or a moderate, reasonable government that forgoes the very strong nationalistic and fundamentalist ideologies that have propelled them for almost 40 years? I have heard two arguments that there is a good chance that Iran will be the latter — that Iran’s government will significantly change for the better due to this agreement. The first is exemplified by the recent statement by Kerry, that one of the key Iranian negotiators told Kerry that if we agree to this deal, it will increase his (the Iranian minister’s) ability to sway other Iranians in the group to consider modifying their behavior, and that he would sincerely try very hard to accomplish that goal. Two issues there: is he simply playing Kerry and even if not, could he sway the others in the group, not to mention the Supreme leader? Would this likely result in the end of the desire to renew the Persian Empire and the spread of their version of Islamic fundamentalism? The answer to both of these is unknown, at best, to be polite to Kerry.

The second argument is that there is a liberal strain among a segment of the population and that by doing this deal and opening Iran up to business with Russia, China, France, Germany, the US, etc, that it will increase the chances for these liberals to gain influence. Sometimes the liberals are referred to as the new generation of Iranians, or the “youth”, though of course the young people there, as everywhere, are split ideologically, some liberal, some conservative, some religiously fanatic, some not, etc. (The Revolutionary Guards and new recruits are not octogenarians). I think this deal is unlikely to strengthen the liberals, and is more likely to weaken them or have no effect, best case. This is because right now, the Iranian economy is weak, and ordinary people have suffered economically. Consistent with most people in other countries, they care much more about their personal financial well being than about issues of foreign policy. As the result, many ordinary people have been upset with the regime because of their economic distresses and in some cases have been open to the idea of regime change including as advocated by some liberals. The end of the sanctions and the economic benefits to come to Iran as a result will decrease dissatisfaction with the regime and decrease support for the idea of taking risks to support the liberals.

Therefore, the most likely scenario is that the Iran which goes nuclear in 15 years will be the Iran of today.

So what are the potential risks of the Iran of today having nuclear weapons? Is there a greater risk than if, say, Denmark, had them, and why? The question is: does their conduct evidence a willingness to murder innocent people? The answer is overwhelmingly yes. Directly and through their terrorist proxies the group, as policy, has done this for a very long time. I will focus first on one of their acts, their bombing of a Jewish community center in Argentina. This was presumably to get at Israel, though the JCC was simply a JCC, as exists in many American cities. The point is that the group, or members of it, decided to blow up the building and kill these people. Sort of like Timothy McVeigh, except here the bad guys have government jobs. Would Timothy McVeigh have detonated a nuclear device if he had the chance? I do not know. Would I take the risk? No. Would it matter if he were in a government position in some dictatorship somewhere? No, I would not take that risk even if he were in a government. (Keep in mind that McVeigh only destroyed one building; Iran has committed and/or funded and/or trained the participants in hundreds of such murders over the years when including its proxies.) Would our Iranian McVeigh (and his allies in the group, however many there may be from time to time) refrain from using nuclear weapons because of the risk that Iran would be wiped out as the result? Probably? Maybe. Might that depend (if they analyze rationally) on whether they believe it could be learned relatively quickly that Iran was behind it? If San Francisco were nuked today, with no claim of responsibility we would counter with a nuclear attack on…whom? North Korea? Pakistan? China? Russia? Perhaps none of the above? Once Iran has a nuclear capability, and also Saudi Arabia and Qatar, and then someone else, with a regime change by someone in the process, might the Iranian McVeighs (or for that matter some bad guys at one of these other places) believe that they could get away with it if they or some terrorist friend detonated a nuclear device? Maybe. I do not want to take that risk. I will only briefly mention that the downside of hundreds of thousands of civilian deaths, and perhaps millions if nations respond, that would result from these scenarios are incomparably worse that the possible negative consequences of a strike against Iran now, even if worse case it led to war.

It is also possible, of course, that the Iranian decision maker might act irrationally. Was it rational when Saddam refused the American ultimatum to allow WMD inspectors into his country –at the threat of annihilation– when he knew he did not have WMD’s? Were the killing fields of Cambodia rational? Was it rational in 1944, when Germany needed all available resources devoted to the war effort, that the Jew haters among them refused to allow many trains to be used for military purposes and instead required that they be used to murder a few hundred thousand Hungarian Jews? To us, it was not rational. To them?

Even though we are focusing on this from the perspective of the US, we still need to analyze whether Iran might use nuclear weapons against Israel if only because the remnants of Israel might respond with nuclear weapons, not to mention that the US or others might get drawn in. How do we assess the degree of risk that Iran would use nuclear weapons against Israel, directly or though a proxy? There is a visceral hatred among many in the group for Israel. The hatred is against the existence of Israel. (The view is that the land on which Israel sits must be controlled by Muslims, not non Muslims, which is why Iran opposed the Israeli offers of a Palestinian state not because of technical disagreements but because they require the non existence of Israel, not an Israel and a Palestine.)

But this visceral hatred does not necessarily mean that the group would use nuclear weapons against Israel. Aside from likely disagreements among some within the group regarding the niceties of murdering so many people at once, they would realize that they would likely be met by some sort of devastating response, if not from the remnants of Israel perhaps from the US. Might the group decide nevertheless to launch two nuclear missiles against Israel (effectively destroying it) and risk nuclear attack in return against Iran? What if the Iranians who make the decision make sure that they and their families are in a safe place, akin to sending waves of suicide bombers (with which they are familiar) while they stay safe? Likely? I do not think so even though there is a belief by some of the group in bringing about the final days though a cataclysmic war. But possible? Yes. How likely? I do not know. De minimis risk? No.

Extremists within the Muslim world occasionally convulse over issues that are irrational to us but very real to them, such as the drawing of blasphemous cartoons. That sort of whipped up fervor could play a role in the decision making.

Aside from the reasons based on their being bad guys or on their religious extremism, there is also the plain old fashioned risk that Iran would use nuclear weapons as a result of their desire to establish their Persian Empire. WWI was triggered by an assassination, but it led to war because the leaders of the countries fell into it and could not get out due to their mutual commitments and egos, to be a bit simplistic. Would they have used nuclear weapons over the course of the war if they had them? Would Iran or someone opposed to Iran? This is not a risk we should take.

The bottom line is that the risks of an Iranian bomb are real and far outweigh the risks of acting now to prevent it.