The sudden death of Iranian President Ebrahim Raisi could have far-reaching implications for the country’s future leadership and policies.

The death of Iranian President Ebrahim Raisi, who died in a helicopter crash on Sunday, could potentially have consequences for the succession of Supreme Leader Ayatollah Ali Khamenei. According to AP, Raisi was considered the main candidate to succeed the 85-year-old leader. After his death, the post could go to Khamenei’s son, which could trigger a potential legitimacy crisis for the Islamic Republic.

Despite regular elections for president and parliament, the Supreme Leader has the final say on all major political issues in Iran. He controls the powerful Revolutionary Guard and appoints half of the 12-member Guardian Council, which vets candidates for the presidency, parliament and the Assembly of Experts. After Raisi’s death, according to the Iranian constitution, the previous vice president Mohammad Mokhber was installed as interim president with the requirement that elections be held within 50 days.

Big changes in Iran are only expected after Khamenei’s death, the report says. The next Supreme Leader will be chosen by the 88-member Council of Experts, elected every eight years from candidates vetted by the Guardian Council. Observers see Khamenei’s son, Mojtaba, as a possible candidate. A transfer of power from the supreme leader to his son could spark outrage not only among critics of clerical rule but also among supporters of the system who might view it as un-Islamic.

After Raisi’s death, the transition period to elect a new supreme leader could become more complicated and potentially trigger more unrest.