The death of Iranian President Ebrahim Raisi sets in motion a scramble to replace him in short order, with long-term implications for the clerical establishment.
Mohammad Mokhber, who served as first vice president under Raisi, has already taken over the presidential duties in an acting capacity.
His time in office will likely be brief, with Iranian law stipulating that a new presidential election be held within 50 days.
Mokhber, along with speaker of parliament Mohammad Baqer Qalibaf and judiciary chief Gholamhossein Mohseni-Ejei, must now arrange a new vote, expected to take place early July.
Raisi died on impact along with nine others, including Foreign Minister Hossein Amir-Abdollahian, when the helicopter they were traveling in crashed in northwestern Iran on May 19.
WATCH: A new presidential election must be held within 50 days following the death of President Ebrahim Raisi, and one analyst says the candidates permitted to run -- be they ultraconservatives or more conciliatory figures who are better able to connect with the public -- will reveal the regime's political priorities.
Raisi, a former judiciary head who was elected by a landslide in a controversial election in 2021, was seen as a protege and possible successor to Supreme Leader Ayatollah Ali Khamenei.
Khamenei, addressing the nation on May 19 before Raisi's death was confirmed, said that "the Iranian people should not worry, there will be no disruption in the country's work."
But the death of the ultraconservative Raisi presents challenges to the Islamic republic's hard-liners, who solidified their hold on power following this spring's parliamentary elections.
Ali Afshari, a U.S.-based former student leader who was jailed in Iran for his activism, told RFE/RL's Radio Farda that "it may not be easy to find a leader like Raisi, who was completely obedient to Khamenei and the establishment.”
The normally lengthy process for determining suitable presidential candidates, all subject to vetting and approval by the powerful Guardians Council, will now be squeezed into a window of less than two months.
In winning the presidency in 2021, Raisi benefitted from the mass disqualification of reformist and moderate candidates. Seen as a hand-picked candidate who would not pose a threat to Khamenei, he took more than 72 percent of the vote in a presidential election that garnered the lowest turnout ever since the Islamic republic was founded in 1979.
There is some precedent for a quick presidential transition in Iran.
The Islamic republic's second president, Mohammad-Ali Rajai, served less than two weeks before his assassination in 1981. He was replaced just over a month later by Khamenei, who took more than 95 percent of the vote in an election in which he was backed by all three other candidates.
Sanam Vakil, director of the Middle East and North Africa program at Chatham House in London, said in a video interview that she expects an expedited process this time around.
"The leadership wants to show a commitment to the constitution, but also business as usual," Vakil said. "And facilitating a quick and accountable election will be important, at least for external constituencies and to show stability."
Vakil lists past presidential candidates who have already undergone vetting by the Guardians Council among Raisi's possible successors, including parliament speaker Qalibaf.
Vakil also said Khamenei could take the opportunity to "rehabilitate marginalized" former parliament speaker Ali Larijani, who was barred from running against Raisi in 2021, but "has been a loyal supporter of the system."
Some observers have also suggested that this might be a chance to repair ties with members of former moderate President Hassan Rohani's camp, Vakil says, although she does not see Rohani himself as a potential candidate.
In 2021, Raisi defeated Mohsen Rezaee, a senior officer of the Islamic Revolutionary Guards Corps who is a member of the influential Expediency Council, as well as Abdolnaser Hemmati, a banker who was the only moderate in the race.
"Who the system picks, or permits, to run will really indicate the priorities or direction of this political establishment," Vakil said. "If they do allow a more contested election, then this could be about building bridges and trying to increase popular legitimacy."
World Reacts To Death Of Iranian President Raisi
On the other hand, if a hard-liner is selected from within the ranks of the clerical establishment, it would show that "the priorities are unity, conservative consolidation, and making sure that transition...continues to be prioritized."
The election of a president this year will also bring changes to election timelines, as the next elected president will serve a full four-year term. This will mean that future presidential elections will fall the same year as parliamentary elections.
Longer-term, Raisi's death leaves a major vacancy in the effort to groom the Islamic republic's next supreme leader, who makes all final decisions regarding Iranian foreign and domestic policies.
Iran's clerical leadership, Afshari said, now finds itself "in an uncomfortable situation" in finding a suitable successor to the 85-year-old Khamenei, who has reportedly suffered from health problems in recent years.
Reza Alijani, an Iranian journalist and analyst based in France, said that former competitors of Raisi would likely benefit. He named Khamenei's son, the prominent cleric Mojtaba Khamenei, as a strong contender to replace his father.
"Mojtaba Khamenei's chances are likely much higher now," Alijani told RFE/RL's Radio Farda.
