The untimely death of President Ebrahim Raisi threatens to disrupt the delicate balance in Tehran. Raisi was killed along with his foreign minister, Hossein Amir-Abdollahian, and other government officials, when their helicopter crashed during inclement weather in a mountainous part of north-western Iran on 19 May. Even though the crash was likely an accident, and regime officials haven’t suggested foul play, it has nonetheless unsettled politics in Tehran. President Raisi was a significant member of the establishment, and his death has forced the regime to undergo a political shakeup at a precarious time. Iran’s simmering conflict with Israel, its longstanding feud with United States, and its advancing nuclear programme have all kept Iran a hair’s breadth from a war. And now, as Iran navigates those treacherous waters, it must also face an unexpected political transition and a reshuffling of the regime’s inner circle.

As the regime and its supporters mourn Raisi and his comrades in official commemorations, many of his detractors inside and outside of the country have celebrated his demise. Raisi was a controversial figure, who had served his entire career as an instrument of Iran’s Islamic system. His professional career began in the early days of the revolution when he was hired as prosecutor in the Islamic Republic’s nascent Ministry of Justice. There he was entrusted with handling the cases of political prisoners, and most notoriously, oversaw the hurried death sentences of thousands of those individuals in 1988. That massive bloodletting, which occurred at the end of Iran’s ruinous war with Iraq, earned Raisi the epithet ‘the Butcher of Tehran.’ Yet, while his complicity in one of the Islamic Republic’s most barbaric and infamous moments stained his reputation in the minds of the regime’s critics, it also solidified his status as a trusted agent inside the theocracy.

Throughout his career, Raisi was entrusted by the regime with increasingly important official appointments, but most his time was spent outside of Iran’s fractious political arena. It was not until 2017 when Raisi first entered the fray as the hardliner’s preferred candidate for that year’s presidential election. He lost that contest to the incumbent, the conservative Hassan Rouhani, but returned to the foray in the 2021 election cycle, where he prevailed against an uninspiring field of regime-approved competitors. Many inside and outside Iran saw that election as a test case for Raisi’s political trajectory. Rumours had already begun to spread that the supreme leader might be grooming Raisi for a higher office still—that of his eventual successor—and that the presidency was being used as a proving ground, or perhaps a stepping stone, toward that promotion.

That line of thinking did not take into account the history of the presidency within the Islamic Republic. With the exception of Ali Khamenei, Iran’s current supreme leader, who served as president in the 1980s, all of the individuals who have served as president in Iran’s Islamic system have had their political fortunes decline after leaving office. For most, their legacies were either stained by the regime’s policies, or they were marginalized by Khamenei himself. Indeed, in many ways, the best way to kill a political career in Iran has been to serve as its president. And while Raisi might have been an exception, his death leaves that question unanswerable.

In a country where the unelected institutions of the supreme leader and the Islamic Revolutionary Guards Corps (IRGC) hold most of the power, Iran’s presidency lacks the influence of a true executive office. Yet, it is still an important post. The president serves as the manager of the government, oversees the budget, and is the chief outward-facing representative of the Islamic Republic. The president also controls the bully-pulpit, especially in international relations, which allowed him a certain degree of influence not afforded to other parts of the regime. It is for those reasons that the presidency has been tightly controlled by the supreme leader, and why the institutions that he has empowered to oversee Iran’s limited democracy have vetoed the candidacies of numerous regime insiders over the last several election cycles.

In recent years, a key aim for the regime has been to deny the office of the presidency to anyone with a hint of personal ambition. That has been especially the case since the tenure of Mahmoud Ahmadinejad, who despite sharing the supreme leader’s politics, and strongly supporting the IRGC’s preferred policies, had become mistrusted due to his bombastic rhetoric and megalomania. The regime’s unelected powerbrokers viewed Ahmadinejad’s personalistic style as a challenge to the system and a threat to the supreme leader’s authority. Following Ahmadinejad’s departure from the scene, Iran’s subsequent presidents have been increasingly politically docile and have lacked any overt personal ambition.

Raisi fit that mould well. It was his mix of ideological orthodoxy, hardliner politics, and lack of ambition that made him both suitable for the presidency and a potential candidate for future supreme leader. In anticipating his eventual death, the 85-year-old Ali Khamenei has already initiated planning for his succession. Raisi was playing a central role in that effort by leading a three-person committee appointed by Khamenei to identify suitable candidates for the post. While no one knows for certain if Raisi was actually a serious contender, the rumours surrounding him suggest that at least a subset of the regime favoured him for the job. Therefore, his death has thrown a wrench into the succession planning, and his supporters will be forced to look for another candidate of a similar ilk.

Alongside Raisi, the other individual most rumoured to succeed Khamenei, is the supreme leader’s second son, Mojtaba. Even though he espouses the correct politics, and is close to the IRGC, Mojtaba’s candidacy is a controversial subject within the regime. Unlike Raisi, who has held various offices in his career, Mojtaba has kept a low profile, and is best known for being a close aide to his father. That position has given Mojtaba immense institutional power within the supreme leader’s office, but also kept him out of the headlines. The consummate political insider, Mojtaba has quietly become a formidable figure within the establishment, but that might not be enough to secure him the leadership. The hint of dynasticism that Mojtaba’s candidacy inherently holds is anathema to the Islamic Republic’s founding character as a theocratic system, which was built on the ashes of a discredited monarchy. Some argue that that is enough to prevent Mojtaba from succeeding his father, and while it is certainly a detriment to his candidacy, the regime’s desire to preserve the status quo might override such sensitivities.

By unsettling the status of the presidency, and perhaps also that of the future succession, Raisi’s death will disrupt Iran’s politics in predictable and unpredictable ways. In the short term, the regime will need to identify suitable candidates for the presidency and prepare for elections that will take place in June. That is no easy task, in particular because most of the prominent politicians within the hardliner faction, which controls the Islamic Republic, have been either side-lined by the supreme leader or lack the trust of the IRGC. That might compel the regime to either attempt to build up a new, credible candidate in the coming weeks, or put their hopes behind an untested individual, such as Raisi’s former vice president and current interim president, Mohammad Mokhber. Otherwise, the regime risks allowing the promotion of an individual already previously side-lined from the top job by the supreme leader or disliked by the IRGC, such as Muhammad Baqer Qalibaf, the current speaker of parliament, or Mohammad Javad Zarif, the former foreign minister. Other relatively outspoken hardliners, such as Ali Larijani, a former speaker of parliament, or unpopular figures, such as Saeed Jalili, a former chief nuclear negotiator and twice failed candidate for president, could also be given an opportunity. The problem with most of those individuals in the past has been the scent of personal ambition associated with them or their sheer unpopularity within hardliner circles. Whether or not such concerns will be of consequence in the regime’s rush to organize the unanticipated election remains to be seen.

Finally, the ripple effects of Raisi’s death are also likely to play out over the medium to long term as the regime searches for a viable successor to Khamenei. At the very least, Raisi had played a pivotal role in overseeing the initial search process, but his rumoured candidacy will also leave a gaping hole in the political field. The power that comes with the position of being the supreme authority of Iran’s theocracy makes the search for its future office-holder fraught. Although Iran’s constitution lays out a formal process for electing a new supreme leader, the process is likely to be determined behind the scenes by a compromise—or fight—between the regime’s main factions, the IRGC chief among them. The process of choosing a successor to Ali Khamenei was already likely to be a fractious process, but with Raisi’s death, that process might now have to begin anew, and finding another consensus candidate is unlikely to be easy or straightforward. Even if the regime in Tehran seemingly survives the current political crisis with minimal disruption, the political reshuffling that will follow is unlikely to be quiet, and its impact could play out for years to come.