The Islamic Republic of Iran has existed in a near-constant state of crisis since its creation following the revolution of 1979. In the face of brutal wars, international sanctions, internal dissent, and an ongoing confrontation with the world’s only superpower, the Iranian government has, so far, managed to amble forward.

Today, the regime is facing one of its greatest challenges yet: a massive wave of popular discontent that began in September with the death in police custody of a Kurdish-Iranian woman, Mahsa Jina Amini. This round of protests has been different from past movements owing to its catalyst: Amini had been arrested for wearing an improper headscarf. Protesters have since been challenging Iran’s mandatory hijab law — an ideological pillar, and tool for social control, of the Islamic Republic. Three months in, demonstrators continue to brave overwhelming state violence to take to the streets with chants of “woman, life, freedom,” with a recent general strike highlighting the still-growing popular anger against the regime.

So far, clerical rule has survived thanks largely to a brutal crackdown. Some 15,000 people have reportedly been arrested. Hundreds more have died in the streets at the hands of security forces. Thursday saw the first execution of a man sentenced owing to protest-related charges. The government, though, is hanging on.

Meanwhile, another major threat looms over the regime, simmering beneath the surface yet rarely breaking into public view. It could prove to be the gravest crisis yet for the Islamic Republic.

Iran’s Supreme Leader Ali Khamenei is aging and reportedly ill. His looming death, with no clear successor in place, puts the Islamic Republic on the brink of a succession crisis — exactly the kind of challenge that has unraveled many authoritarian regimes in the past. The crisis may soon empower one of Iran’s powerful security organizations, the Islamic Revolutionary Guard Corps, or IRGC, to take a direct role in governing Iran for the first time in its history.

When protests broke out this September, Khamenei, whose supporters had expected him to deliver a public response, was rendered absent due to lingering ill health from a recent bowel surgery. In recent years, Khamenei, who is 83, has been stricken by an array of serious ailments, including prostate cancer, but has also survived many past predictions of his imminent death.

Though he has since appeared in public to denounce the recent protests as foreign subversion, it is worth considering what Iran will look like, both in terms of domestic and foreign policy, after its supreme leader finally departs from this world. The most recent wave of public rejection towards his regime only serves to emphasize how stark the coming changes may be.

“It is something that almost nobody discusses openly inside Iran, but the whole country is now bracing itself for the issue of succession.”

“Khamenei’s passing will pose a significant challenge to the Islamic Republic because whoever succeeds him will be from a generation that did not participate in the revolution. It is something that almost nobody discusses openly inside Iran, but the whole country is now bracing itself for the issue of succession,” said Sina Azodi, a lecturer on international affairs at George Washington University. “Khamenei took part in the 1979 revolution and was even imprisoned by the Shah’s secret police, the SAVAK, whom he considered stooges of the United States. He has been very skeptical of Western intentions towards Iran, and, once he leaves the scene, one of the major impediments to Iran’s improvement of relations with the West would be gone.”

Khamenei, who became supreme leader in 1989, has ruled Iran almost four times longer than his one and only predecessor, Ruhollah Khomeini, the leader of the revolution and founder of the Islamic Republic. In many ways, the regime that exists today is his own personal creation, and the management of competing power centers inside Iran is dependent on his role as final authority. Khamenei has marginalized most of his competitors inside the clergy, solidifying himself as a near-unquestioned authority within the system. This monopolization of power and influence, common to dictatorships, has made his own place secure, while calling into question the system’s ability to adequately replace him after he dies.

Despite his singular power, factions have emerged inside Iran’s security establishment that may be ready to capitalize on Khamenei’s demise. Most prominent among them is the Islamic Revolutionary Guard Corps, a branch of the armed forces created after the 1979 revolution as an ideological armed service. Today, the IRGC is perhaps the only force inside Iran left with both the strength and incentive to take a direct role in Iranian politics after Khamenei is gone.

Designated as a terrorist organization in a controversial decision by the Trump administration in 2019, the IRGC today is no longer just a military force under the command of the supreme leader. It is also a major economic player inside Iran, owning lucrative businesses and real estate holdings that it will likely seek to preserve regardless of what changes may come in Iranian politics. Understanding the level of mafia-like control that the IRGC exerts over Iranian society today is key to understanding what the country’s politics may look like once its leadership is fair game.

“Looking at their behavior, the IRGC seem primarily interested in their own material benefits, they are not simply ideological. They are in the business of making money, unlike Khamenei, who, at least on the surface, has tried to show some degree of modesty,” said Azodi. “These people are interested in protecting their economic advantages, and they have benefited from international sanctions. They control not just the visible economy but much of the black market. All the luxury goods that come to Iran today arrive through channels controlled by the IRGC.”

Experts say it is highly possible, even likely, that an economically powerful and well-armed IRGC leadership may decide to stage a military coup to take direct control over Iran after Khamenei dies.

Such a coup need not be overt. Many other countries in the region, most famously Egypt and Pakistan, are run from behind-the-scenes by powerful military establishments, even while they maintain a patina of civilian government. Such arrangements have not usually benefited the citizens of these countries, but they have worked quite well for military elites themselves. There is no reason to think that powerful figures in the IRGC would be averse to such an opportunity, nor that they would restrain themselves from seizing it if it emerges after Khamenei’s passing.

The issue of how a possible IRGC-led regime would govern Iran, particularly with regards to the restrictions on personal freedoms that are at the heart of many Iranians’ grievances today, will depend on how its leaders view the continued usefulness of Iran’s clerical establishment.

The Islamic Republic was created as a theocracy, a feat pulled off in no small part thanks to the reverence for clerical authority in the Shia sect of Islam that dominates Iran. Today, though, popular anger over its misrule is increasingly directed at members of the clergy themselves. In addition to personal attacks against Khamenei, Iranians have taken to posting viral videos of themselves slapping the turbans off clerics’ heads as they walk down the street — a visible indication of how far the credibility of this institution has fallen in the eyes of the public. The dim perception of the clergy among ordinary Iranians is likely to play a role in how a possible military-led government may behave.

“With the IRGC as de facto leaders of the Islamic Republic, its stance on domestic issues depends on its leadership’s perception of the question of legitimacy and the role of the Shia clergy,” said Ali Alfoneh, a senior fellow at the Arab Gulf States Institute, and author of “Political Succession in the Islamic Republic of Iran.” “If the Shia clergy is still perceived as a source of legitimacy, the IRGC will continue restricting personal freedoms on religious grounds.”

“Iranian youth spending their free time on sex, drugs, and rock-and-roll can buy an IRGC military dictatorship at least ten years in power.”

Alfoneh went on, “If the IRGC leadership no longer perceives the Shia clergy as a source of legitimacy, it will throw them under the bus and likely give personal, though not political, freedoms to the Iranian public. Iranian ladies wearing mini-skirts, and the majority of Iranian youth spending their free time on sex, drugs, and rock-and-roll can buy an IRGC military dictatorship at least ten years in power.”

There is little sign that the IRGC is ready to make a move for power any time soon, particularly while Khamenei himself may beat the odds again and survive for some years to come. Yet his inevitable departure from the scene, absent a clear successor either chosen by him or allowed to emerge organically from within the clerical establishment, means that a future picture of Iranian politics is already hazily visible on the horizon.

An Iranian government run by the IRGC — either directly as a military dictatorship or, more likely, with a puppet supreme leader under its control — may not just change some of Iran’s domestic policies, but also its approach to the international community.

To be sure, an Iran run by its security elites would not be a democracy. Yet it would likely return to a pragmatic position regarding its relationship with Israel and the West, if not the countries of the Arab world. Though it would fall short of the demands of protesters in the streets today calling for democratic change, such a regime may still transform Iran into something like a socially liberal Saudi Arabia — acceptable to Western interests, no doubt thanks to its richness in fossil fuels, yet still authoritarian at its core.

A relatively pragmatic system such as this is likely to come into existence, regardless of any future ideological changes that may mark an IRGC-run regime after Khamenei’s death, Alfoneh said.

“The IRGC has had excellent relations with Israel and the United States in the past: From 1979 until 1988, Israel was the primary source of the IRGC’s procurement of U.S. produced arms, and the IRGC has also on multiple occasions engaged in tactical alliances of convenience with the United States against the Taliban and against the Islamic State,” he said. “I see no reason why these patterns of behavior should not continue seen under an IRGC-ruled Iran.”

Though its foreign relations could be revised, Alfoneh cautioned that some things just won’t change. “As for more fundamental issues, such as Iran’s nuclear ambitions, missile program, support to proxies, and opposition to great power presence in the Persian Gulf, there will be no change as long as Iran exists as a unified political entity,” he said. “Even if the Islamic Republic collapses, Iranians collectively convert to Zoroastrianism and revive the Sassanid Empire, all these policies will continue as before.”