In 1963, the young Harvard professor Henry Kissinger contemplated how the United States might approach a rapidly growing Soviet nuclear program. In doing so, he described the dilemma of the statesman as “the choice between making the assessment which requires the least effort or making an assessment which requires more effort.” Six years ago, Kissinger’s biographer, Niall Ferguson, invoked this “problem of conjecture” to consider the Iran nuclear deal. The problem of conjecture remains an apt prism through which to think about Iran’s nuclear program because as in Kissinger’s Soviet example, whatever a policymaker does about the program, he will “never be able to prove that his effort was necessary. . . . If he waits, he may be lucky or he may be unlucky. It is a terrible dilemma.”   

Conjecture is the simultaneous attempt to interpret the present and to guess how the future will unfold. In the wacky world of punditry, conjecture about Iran’s nuclear program usually falls into one of two camps. The first argues that Iran is rushing towards nuclear weapons in order to fulfill a destructive, messianic ambition. The other argues that Iran’s push towards nuclear weapons can be indefinitely restrained by agreements like the Joint Comprehensive Plan of Action. Both assessments are what Kissinger referred to as “assessments which require the least effort.” A different conjecture, which admittedly requires more effort, would view the danger of a nuclear Iran through a prism that unites most of the modern Middle East’s problems: an endemic deficit of legitimacy, and the consequent potential for political instability.   

The argument that the Islamic Republic desires nuclear weapons to annihilate Israel in an orgy of messianic fervor is fantastical. The evidence suggests that, far from being a nuclear suicide bomber, the Islamic Republic is obsessed with survival. A regime that regards itself as the standard-bearer of the Islamic world and is consumed with the violent repression of domestic protest is not a regime with a death wish. The function of the Islamic Revolution was, in the words of Ayatollah Ruhollah Khomeini, to create “a point in the start of the revolution of the great world of Islam.” This sense of mission has persisted to this day: it is the bedrock of the regime’s identity and gives the regime a will to survive, not to die. The idea that Iran would commit suicide with a first strike is far-fetched. But the argument for keeping calm and carrying on is just as thin.   

The argument that Iran will rush to obliterate Israel after acquiring nuclear weapons enables Iran’s apologists to caricature those worried about a nuclear Iran as swivel-eyed doomsayers. Yet Iran’s nuclear research has gone far beyond performative provocation, and its leaders boast a consistent fifty-year track record of calling for the destruction of Israel in addition to threatening Saudi Arabia and the United Arab Emirates with the same demise. Ignoring the pace of Iran’s nuclear research and the extraordinary record of Iran’s threats is absurd. For that reason, both types of short-term conjecture are too short-sighted. In reality, however, if Iran does cross the nuclear threshold, the danger will come not when Iran acquires nuclear weapons but quite some time afterward. 

“If Sparta and Rome have perished, what state can hope to last forever?” This was Jean-Jacques Rousseau’s pessimistic assessment in The Social Contract. It holds especially true for the Islamic Republic. Iran’s population is becoming younger, much more secular, and more connected to the rest of the world. The regime’s authority is the product of a unique moment in history. Its authority will continue to dwindle as the Iran of today moves further away from the revolutionary moment in which it was conceived. Endemic corruption and economic mismanagement will continue to undermine a regime based on moral purity and will create the conditions for revolution. Dreams of the Islamic Republic becoming a flourishing “Islamic Civilization” are as premature as the late shah’s dreams for the Persian Empire. If the collapse of the Islamic Republic is more a question of when than if, then the question then begs: what happens after the fall?   

From the deposition of the Sassanids by Iran’s nobles to Nader Shah’s 1736 counterrevolution to the 1921 Cossack coup that brought the Pahlavi family to power, Iranian regimes have historically succumbed to mutiny. Today, overwhelming popular unrest would likely see the Iranian Islamic Revolutionary Guards Corps, the modern equivalent of the Cossacks, come to power. They would do so by rescuing, not deposing, the revolutionary system. Were this to happen, Iran’s foes would be unlikely to resist the temptation of outfitting Iran’s armed domestic opposition groups. A bloody civil war could ensue. The regime could use nuclear weapons against backers of insurrection or could threaten to do so, bringing about a first nuclear strike on Iran. And if the regime really stood no chance of survival, it could opt for messianic suicide, taking Riyadh and Tel Aviv down with Tehran. This marriage of nuclear weapons with an unstable regime would make feasible contingencies much more dangerous. But not just in Iran.   

Were Iran to acquire nuclear weapons, Turkey, Saudi Arabia, and possibly Egypt would move to do the same. For Saudi Arabia, it is an official position; Turkey has intimated that it would follow suit, and Egypt began hedging when early revelations about Iranian nuclear weapons appeared in the early 2000s. Some argue that the region would break into peace under the shadow of a Damocles’ mushroom cloud. Yet while mutually assured destruction is perhaps reasonable for most states, Iran and the countries that would follow in its nuclear footsteps are susceptible to state collapse. Adding a nuclear element into such contingencies would be extraordinarily dangerous.   

Saudi Arabia is currently in the process of renegotiating its social contract. A Saudi nuclear weapon would enormously raise the stakes of the kingdom’s successful political and economic transition. The outcome of that transition is far from certain. If it fails, then Saudi Arabia lacks any deeply rooted institution that could take over. The endurance of radical Islamist groups in the kingdom—as well as historic attempts by those organizations to seize the reins of power—offers a grim picture of where a Saudi nuclear weapon could go. While the risk of a Saudi nuclear weapon is the uncertainty of the kingdom’s political future, for Turkey, it would make the country’s current trajectory much more dangerous.

With its rapid march towards authoritarianism and a determined ideological agenda, Turkey’s ruling AK Party is transforming its political system and engendering a broad domestic opposition. The military has been purged since a 2016 coup attempt, and the AKP has since developed a band of well-armed partisans. It now has plans for constitutional reform which will most likely prolong President Recep Tayyip Erdogan’s stay in the exorbitant White Palace. Beyond the AKP’s plans for how Turkey should look at home, it also has an expansive agenda for what Turkey should be doing abroad. With nuclear weapons, the AKP would likely press ahead with its ambitious regional agenda. Its record of using foreign policy crises to bolster its popularity could lead to a third marriage of nuclear weapons and regime stability and would give the world yet another unwelcome gift of more nuclear brinkmanship.

Since the Arab Spring, little progress has been made in creating durable bases of political legitimacy in the region. This undermines political stability and creates opportunities for ideological fanatics to take the reins of power, in Iran and across the region. The danger of a nuclear Iran must be understood in this context, and Iran’s own history best demonstrates the risks at play. Had the shah succeeded in acquiring nuclear weapons prior to the Islamic Revolution, then those weapons could have fallen into the hands of today’s regime. The next fifty years provided numerous occasions whereby those weapons could have been used against Iraq, Saudi Arabia, or Israel. Were Iran and its neighbors to acquire nuclear weapons, then the potential for such counterfactuals to occur in real life would be greater than ever.   

Crises, like pandemics, come in multiple waves. Contingency produces contingency, and nowhere would this be more the case than an Iranian nuclear weapon. The danger of a nuclear Iran is that it would enable extraordinary, entirely plausible contingencies to take place by arranging the marriage of nuclear armament and political instability in not just one, but at least three instances. The JCPOA is more likely than not to be reinstated in Vienna by the end of this year. If it is successful, then it will delay Iran’s nuclear ambitions for another decade at most. Yet this policy is the product of short-term conjecture. Most people are tired of hearing about Iran’s nuclear program because it has been given too much attention and treated with too little detail. Teasing out the longer-term consequences of vexatious foreign policy questions can require some effort but offers a view into the profound consequences of action and inaction. The problem of conjecture is alive and well with Iran and presents a terrible dilemma.