Center for a New American Security’s report and its weakest link

The Center for a New American Security has come up with a detailed report on the consequences of Iranian nuclearization  titled Risk and Rivalry  - Iran Israel and the Bomb

On page 13 the report cites the famous Bernard Lewis quote:

 According to Middle East scholar Bernard  Lewis, “in this context, mutual assured destruction, the deterrent that worked so well during the Cold War, would have no meaning.”

But it seems that the report does not consider this statement valid since on the same page it states:

Despite the abhorrent and inexcusable rhetoric of Iranian leaders, the actual behavior of the Islamic Republic over the past three decades suggests that the regime is rational. Consequently, there is a high probability that nuclear deterrence between  Israel and Iran would operate much as it did for the  superpowers during the Cold War.

As the Washington Institute for Near East Policy’s  Michael Eisenstadt notes, the perception of Iran as  irrational and undeterrable is “both anachronistic  and wrong.”

 While Iran’s revolutionary leadership has repeatedly supported Islamic militancy and used violence abroad to promote its ideological agenda, Iran has also demonstrated a degree of caution, sensitivity to costs and the ability to make  strategic calculations when the regime’s survival is  at risk.

There is no evidence for the claim that Iran  is a suicidal state that would be willing to incur the  massive retaliation that would inevitably result from the use of nuclear weapons. This is unsurprising since the continued survival of the Islamic Republic  is necessary to achieve every one of the regime’s material and ideological objectives, including the success of the revolution at home and the spread of Iran’s Islamist model abroad.

Even assuming that the threat of annihilating Israel by Iranian religious leaders is rhetoric, the Bernard Lewis quote still applies to Ahmadinejad and his group, as acknowledged by the authors of the report themselves (page 17):

Apocalyptic Cults and a Collapsing Regime

Even if Iran’s current regime is rational, the regime could change in ways that make deterrence less viable.

Some fear that leaders embracing an apocalyptic variant of Shiism (sometimes referred to as the “cult of the Mahdi”) might eventually seize control of the regime. On the surface, this seems plausible because President Mahmoud  Ahmadinejad and some individuals within the  IRGC appear to subscribe to these beliefs.

 Such  messianic leaders might nihilistically welcome  destruction to usher the return of the Twelfth  Imam and the “day of judgment.”

Although it is impossible to predict the precise course of future events in Iran, this scenario seems  unlikely  Adherents to the cult of the Mahdi are a distinct and increasingly marginalized minority  in Iran, largely composed of ultraconservative lay people who are reviled by the traditional clerical establishment (including Khamenei).

 The  entire notion that nonclerics could have contact  with the Mahdi is so inherently threatening to the  clerical establishment and the institution of the  supreme leader that it is hard to see how they could  come to dominate the Islamic Republic. Indeed,  the 2011 power struggle between Khamenei and  Ahmadinejad, in which Khamenei emerged the  victor and the IRGC leadership overwhelmingly  sided with the supreme leader, included a prominent crackdown against Ahmadinejad’s allies for  their supposedly “deviant” views.

So essentially, the conclusions and recommendations of the report hinge on the assumption that the possibility that the apocalyptic variant of Shiism (sometimes referred to as the “cult of the Mahdi”) might eventually seize control of the regime is unlikely. ( At this moment Khamenai and the clerics are in power, although Ahmadinejad is the president).

What is the probability of the worst case scenario? That the apocalyptic variant of Shiism does take control? Five percent? Ten percent?  Considering the catastrophic consequences of such a scenario should not Israeli and US policy be mostly focused  towards preventing  such an outcome?