TEHRAN, Iran » Far from the flashing cameras and microphones in Vienna, where Secretary of State John Kerry is joining Iranian and U.S. diplomats in a final push to reach a compromise on Tehran’s nuclear program, a different sort of political drama unfolded in the Iranian capital this week: Hard-liners got together to criticize the objects of their "worries," as they put it, the moderates advocating a deal.

"My brothers, we are in danger," one of the conference organizers, Ali Hassanzadeh, told the audience, as a video portrayed the moderate president, Hassan Rouhani, and his negotiators as gullible tools of the United States.

In Iran, the final decision on a nuclear deal lies with Ayatollah Ali Khamenei, the supreme leader. And if history is an accurate guide, the real debate over an accord, should one be reached, will not begin to unfold until after it is announced. When that debate gets underway, the voices of the hard-liners — the clerics, Republican Guard commanders, conservative lawmakers and others who are by and large closest to the supreme leader — will be raised against any compromise on Iran’s right to enrich uranium.

But there is another developing line of thought in Iran that is far more hopeful and reflects the desires of many urban Iranians. Some insiders say that a nuclear deal is being planned by powerful figures in the Iranian leadership as the start of a fundamental shift in Iran’s ideology, aimed not only at normalizing relations with the world but also at rebranding the now 35-year-old Islamic revolution, turning away from its founding principles of anti-imperialism, anti-Americanism and strict limits on personal freedoms.

There was nothing of that in the air at the state-sanctioned hard-liners meeting, however, where copies of a book of speeches by Khamenei, with a title taken from one of his most famous quotes, "I Am a Revolutionary, Not a Diplomat," were selling well for around 50 cents a copy.

Inside the auditorium, a smiling young man led a lone foreigner to a seat, as a cinema-size screen showed portraits of several Iranian nuclear scientists who were killed from 2010 to 2012, "by the Americans," as one speaker insisted.

"What are these nuclear dealings that no one has information about?" asked one cleric, Hamid Rouhani, no relation to President Rouhani. "It is as if we have returned to the time of the monarchy, with secret deals without involvement of the people."

Summing up their position, one young man held up a yellow placard proclaiming: "No Compromise. No Submission. Only Fighting with America."

The ease and confidence with which hard-line representatives organize such meetings — where visitors walk over U.S. flags and, recently, shout things like "Death to Obama" — is a sign of their deep hold on power in Iran. In contrast, Iran’s Interior Ministry, which is controlled by the government, has not allowed public rallies or meetings to denounce the negotiations.

"In the name of our almighty God, who is greater than American imperialism," said Alireza Mataji, a 26-year old organizer of the event, "we are granted permits for meetings because we represent the people and pay ourselves."

Their march to power, which has given them control over the judiciary, Parliament, the security forces and large parts of the economy, was partly facilitated by Iran’s leaders. That has made people like Mataji loyal foot soldiers and firm ideological believers.

The hard-liners say they operate under the banner of Iran’s leader, Khamenei, who has repeatedly warned that he is "not optimistic" over the chances of reaching a nuclear deal with West and particularly the United States, which he regards as Iran’s archenemy.

"We will witness the leader coming out after a bad deal with a speech elaborating on why the United States cannot be trusted," Mataji said. "All except some wealthy people who are ready to sell out the country’s sovereignty will understand the deceiving nature of the Americans."

Still, Khamenei has also publicly stated that no group can actively oppose the Iranian nuclear negotiators during the talks, labeling them "children of the revolution." While expressing his doubts, he has emphasized that when talking to the enemy "heroic flexibility" can be a tactic in achieving Iran’s goal of escaping sanctions while keeping its right to enrich uranium and pursue a peaceful nuclear program.

In recent weeks, commentators here say, hard-liners have swallowed hard and followed Khamenei’s lead in supporting the nuclear team, outwardly, at least.

"They stand to lose power, money and influence if the deal happens," said Saeed Laylaz, an economist close to the government. "Naturally, they are worried, but they will be isolated as many of the wealthy and key figures will join those leading the changes that are inevitably coming."

Failure to complete a deal and a breakdown in the talks, many here say, would almost surely make Rouhani, the main promoter of détente, a lame-duck president, ending any chance of his executing his agenda of more personal freedoms and better international relations.

If a deal is reached, though, they say the opposite could happen, and those who have been marginalized over the years by the hard-liners — the reformists, centrists, moderates and groups that have long and unsuccessfully promoted change — will be the beneficiaries.

Surprisingly, a political adviser long aligned with Iran’s hard-line faction predicts that this is precisely what is going to happen, with Iran repositioning itself following a successful agreement. "If there is a deal, and if it is good, the entire system will go along with it," said the adviser, Amir Mohebbian, who is close to several prominent Iranian leaders. "There will be a huge political shift after a deal."

He said that with the rise of Sunni radicalism in the Middle East, Iran’s ideology of radical resistance against imperialism needs an update. "We strive to be the leading nation in the Islamic world, and faced with the Islamic State it is much better for us to attract support if we represent a moderate version of Islam. We still demand justice, but will try to get it in another way."

Mohebbian’s views, based he says on contacts with the highest circles of Iran’s establishment, are taboo, publicly, at least, among those holding power in Iran. But they are attuned to many if not most middle-class Iranians, who increasingly feel alienated from the rigid ideology that has remained frozen in time since the 1979 revolution.

"It is my conviction that those who make decisions within the system want it to be alive and supported," he said. "For survival, we need change."

Such a scenario may seem far-fetched, in that consistently at critical moments over the past 15 years, Iran’s leaders have thrown in their lot with the hard-liners, suppressing protests and promoting laws like a recent one against dog ownership to maintain harsh Islamic discipline.

"I am not saying we are Switzerland," Mohebbian said. "We have learned from history that if leaders show weakness, they lose. But now our leaders feel strong and confident, so this is the moment for change."

Hard-liners laughingly dismiss such ideas.

"Even if there is a deal, Mr. Rouhani and like-minded people will be losers because it will not bring the prosperity that they have promised," said Mataji, the engineer and organizer of Monday’s conference. "Anybody who thinks this will bring about ideological change must be joking."

But Mohebbian insisted change was coming. All the stars have aligned, he said, the society is beyond ready, and regionally Iran is strong and the United States confirms that. He pointed to Iran’s military successes in the region, the fact that in Yemen pro-Iranian rebels had seized power, that Iraq was under even more Iranian influence and that the United States seemingly had abandoned plans to remove Iran’s ally in Syria, President Bashar Assad.

"The fact that Obama writes letters directly to our leader Khamenei highlights Iran’s importance and confidence," Mohebbian said. "This is a golden moment for us."