Is regime change in Iran possible without a united opposition or clear alternative leader?

More than 46 years after the Iranian Revolution, there is still talk among Iranians — both those living in the country and among the diaspora — that the end of the regime is nearing.

"It [the Islamic Republic of Iran] will not survive … whether they like it or not change is coming," says one Iranian in Hamadan in western Iran speaking to ABC News.

It's the early hours of the morning in Iran.

US President Donald Trump has just announced on social media that he's brokered a ceasefire between Israel and Iran.

Eventually Israel and Iran agree to end attacks on each other, and Mr Trump will change his tune on the possibility of regime change in Iran, saying he doesn't want to see "chaos" in the Middle East.

But at this moment, when I join the chat group with Iranians speaking in Farsi, talk of a ceasefire is still up in the air and attacks are continuing.

These Iranians are debating — some joking — about which airports Iran's leaders may be using to escape to other countries. I introduce myself and ask them how they are feeling post news that there may be a ceasefire.

The feelings are mixed. Some are happy that the conflict could be over and say regime change should come from within rather than through any foreign intervention.

But some also didn't want Iran's government to be thrown a lifeline and say had Israel further weakened the regime's apparatus, it could have paved the way for another uprising.

I have promised to keep the identities of these young Iranians — aged in their late 20s to late 30s — anonymous as revealing it could endanger their lives, especially at a time when human rights groups including Amnesty International report scores of arrests across the country for alleged "espionage" or "collaboration" with Israel, along with "chilling" orders for expedited trials and executions.

These young Iranians believe that after decades of civil unrest, and with Israel's recent attacks on the regime, there is no way the country's rulers can indefinitely cling on to power, but they seem less certain about how change will happen and who will lead it.

In fact, there's much disagreement over who should step in to lead if the regime falls — should it be political dissidents locked up in Iranian jails or so-called "reformist" elements of the regime?

Or should it be Iranians outside the country — like the US-based exiled Crown Prince Reza Pahlavi — who have for decades floated the idea of a secular democracy?

This is as contentious among the Iranians in this chat group as it is among experts who have spent decades researching and writing about Iran.

Experts who spoke to ABC News say unless and until large factions of the regime's military, police and intelligence forces begin defecting, it will be hard for the people of Iran to overthrow the regime.

And, as history in the Middle East has shown, while citizens may desire democratic change, the pathway to freedom is often fraught.

Need for a united opposition

US-based writer and historian Arash Azizi, who has firmly been opposed to the regime, argues the Islamic Republic knows that its ideals are not popular in society, yet its general apparatus is still intact.

The Islamic Republic, he argues, stays in power for two primary reasons: "One; sheer brutality, and two; a lack of an organised alternative."

For the people to overthrow the regime, he says there would need to be an organised opposition with "political heft" that can unite Iranians of different faiths, ethnicities, and political persuasions.

"This could theoretically be a liberal democracy that's a common demand for the opposition, but the Iranian opposition is more divided and incoherent than ever," Mr Azizi says.

It was the major difference in 1979 when there were organised efforts against the shah, and it was "the unifying leadership of Ayatollah Khomeini who brought Marxists, Islamists and nationalists together against the shah".

Can the exiled crown prince play a transitional role?

Some Iranians now living around the world still long for a return of the Pahlavi dynasty and see the son of the former shah, exiled Crown Prince Reza Pahlavi, as the best option.

Crown Prince Pahlavi has been talking about regime change for 46 years.

He has spent most of his life outside Iran, in the United States.

The crown prince has consistently said he would only play a "transitional role" towards a new secular democratic Iran. Then, he says, it is up to the people of Iran to choose their own leader from within.

"I am stepping forward to lead this national transition — not out of personal interest but as a servant of the Iranian people," he said at a press conference in Paris on Monday.

He added that he would establish a "secure platform" for military, security, and police personnel who wish to defect from the regime to directly contact him and his team.

In the chat group, I ask the young Iranians participating whether they think the exiled crown prince can lead a transition.

The Iranian man living in Iran near Hamedan thinks it's not possible, saying it would take time to establish a liberal democracy.

He mentions potential leaders could come from "reformist" elements of the regime such as Hassan Rouhani, an Iranian religious cleric and politician who previously served as president of Iran.

He also mentions political dissidents including Iranian human rights activist Narges Mohammadi — who has been a vocal critic of the regime using sexual violence against women.

She was arrested 13 times and sentenced to 31 years in prison and 154 lashes. In October 2023, when her selection as the Nobel Peace Prize laureate was announced, she was locked in Tehran's notorious Evin prison.

"These are the liberals of Iran … and they have power within Iran," the Hamadan Iranian argues focusing again on Rouhani.

But before he can elaborate on this thought, another Iranian in the chat group interjects, saying: "If Rouhani or any of the reformist elements [of the regime] are brought forward, they are not motivated to bring down the regime … Their hands are dirty."

For that reason, he thinks Reza Pahlavi is a far better choice.

"Bring Pahlavi's name and every Iranian knows him. It's very important to have recognition," he says.

Will the people rise up?

But revolutions don't occur without mass civil uprising.

Roya Boroumand, the executive director of the Washington-based Abdorrahman Boroumand Center, which works to promote human rights and democracy in Iran, says while she wants to remain hopeful, she's not certain Iranians can, once again, mobilise and protest for regime change.

"This [regime change] requires a really mobilised and unified opposition, asking people to strike, asking people to show resistance in a very intelligent way," she says.

She also rejects the idea that regime "reformists" can lead Iran to a democracy.

She says during the 2009 Green Movement protesters disputed the election of the then incumbent president Mahmoud Ahmadinejad. They turned to the streets in support of opposition candidates including Mir-Hossein Mousavi and Mehdi Karroubi.

This, she explains, was based on the idea at the time that they were more centrist politicians.

She says up until this point, the survival of the Islamic Republic was not under threat.

"It was more discussion about reform of the Islamic Republic rather than getting rid of it, and the so-called reformist movement was part of the ruling elite," Ms Boroumand says.

By 2019, the idea that the regime could reform itself was waning, as the Iranian people's deep economic troubles saw their discontent grow into anti-government protests.

A 50 per cent plus spike in fuel prices led to calls to overthrow the regime. This became known as the Bloody Aban (Bloody November) protests, which spread across Iranian cities and left up to 1,500 people dead according to Reuters.

By 2020, Ms Boroumand says support for the regime continued to diminish. That was the year Ukraine International Airlines Flight 752 was shot down by the Islamic Revolutionary Guard Corps (IRGC) shortly after take-off, killing all 176 occupants on board.

And by 2022, with the death-in-custody of Mahsa Jina Amini, protests spread from the cities to rural areas.

Once again, these protests were met with regime brutality.

The Human Rights Activist News Agency estimated about 500 people were killed and more than 20,000 were arrested, with Amnesty International accusing Tehran of conducting "sham trials" that resulted in executions.

Ms Boroumand says the 2022 protests and the resulting violent crackdown by the state, have brought out a "more diverse spectrum of the population that is clearly against the state and want it gone".

She says the international community has brought greater focus on the regime's human rights violations, citing the UN Fact Finding Mission on Iran, the expelling of Iran from the UN Commission on the Status of Women, and world leaders globally expressing solidarity with the women of Iran as examples.

A road map to democratic change?

Mariam Memarsadeghi, a senior fellow at the Macdonald-Laurier Institute in Washington, also argues the road map to regime change is not clear when dealing with a "totalitarian regime that is really bad in almost everything other than taking on the opposition".

She doesn't throw her support behind any individuals but says before there can be talk of regime change, there needs to be systems created that enable a democracy to evolve.

"It's really important, particularly in the case of a country like Iran coming off of nearly half a century of totalitarianism, that security is established, a sense of stability is felt across the country.

"That the beginnings of democratic institutions are taking shape — an independent judiciary, a school system that is democratic, that actually focuses on development of children and learning opportunities rather than Islamist ideology.

"When you have all of that … people feel the freedom and the critical thinking to be able to elect leaders that represent them and represent their interests."

Are defections among the regime still possible?

Kylie Moore-Gilbert, Australian academic and former political prisoner in Iran, explains that in every major revolution in history we've seen defections.

"And unfortunately, in every protest movement in Iran since the [1979] revolution, that hasn't happened — the protesters haven't convinced significant individuals within the regime to step away and join them," she explains.

Dr Moore-Gilbert says there is also the reality that there are "sizeable ethnic groups like the Kurds, who will be calling for greater autonomy as well, and they could act as spoilers if some kind of central opposition government was established".

"A lot of these issues need to be ironed out," she says.

While US President Donald Trump has said he wants the war to stop, she fears that if regime change is once again on the table, there is a danger of Israel or the US "attempting to force their will on the people of Iran".

Saeed Ghasseminejad, a senior adviser on Iran at the Foundation for Defense of Democracies (FDD) — a Washington DC-based think tank that is viewed by some to be pro-Israel's government and anti-Iran's government — argues Israeli attacks on Iran have weakened it and paved the way for defection.

He says there is a segment of supporters of the regime that are "brainwashed" and will never defect.

But there are others who serve the regime because "they are getting lot of benefit in a society" including economic gains, and that "there is a chance of defections".

He fears a greater level of oppression and violence if the regime remains in power in the wake of the conflict with Israel and the US.

Back in the chat group, there's a young woman who moved from Iran to Europe in 2017 but seeks to return one day.

She is in constant talk with family and friends in Tehran.

"They [Iran's authorities] are checking everyone's mobiles — to see if they can find collaborators with Israel," she says.

Asked whether regime change towards a democracy will now eventuate, she says it "will inevitably happen because that is the will of the Iranian people".

She says Iranians spread around the world left Iran for a better life but seek to return under a democracy.