ISTANBUL—It’s been a busy time at Iran’s Supreme National Security Council. For months, top officials from the country’s political and security establishment in this most exclusive club have been debating, discussing and deciding how the country will respond if U.S. President Donald Trump scuttles the nuclear deal forged with the Obama administration and five other world powers.

Although the minutes of the SNSC meetings are never made public, those with a seat in the circle of power—including Supreme Leader Ali Khamenei—are well known, and their pronouncements offer diplomats, spies, and scholars clues as what Iran will do if Trump steps back from the 2015 deal.

“Obviously, the decision lies in the Supreme Leader’s hands,” said Mehran Haghirian, a Tehran-based political scientist and researcher. “Some of the decisions are already made. They have plans; they all depend on what action will be taken by the U.S., specifically, what types of sanctions.”

The sanctum sanctorum of the SNSC is in a heavily guarded central Tehran compound just to the north of Khamenei’s headquarters. Surrounded by grey streets choked with traffic, the verdant enclave centered on the Marble Palace built by Iran’s Reza Shah in 1937,  is an old-world respite from the chaos of downtown Tehran outside.

When important matters of national security are at issue, the top officials of Iran’s political and armed forces sometimes sit cross-legged in a room, according to photographs of a meeting published online. Other times they sit in chairs when they meet visiting foreign dignitaries or consult with specialists. Always there are portraits of Iran’s revolutionary founder Ayatollah Ruhollah Khomeini hanging on a wall.

Officially, the SNSC is a think tank. The discussions are cerebral, scholars have said, rooted in the hermeneutic traditions of the senior Shia clergy who took control of Iran during the 1978-1979 revolution.

Iran’s president, now Hassan Rouhani, chairs the council’s meeting, with former defense minister Rear Admiral. Ali Shamkhani serving as secretary.  Parliamentary speaker Ali Larijani, his brother judiciary chief Sadegh Larijani are there, along with the ministers of defense, interior and intelligence, as well as the head of the powerful Iranian Revolutionary Guard Corps.

Javad Zarif, Iran’s Twitter-savvy Anglophone foreign minister, gets a seat at the table, as does Saeed Jalili, who served as secretary of the SNSC and chief nuclear negotiator under the hardline Mahmoud Ahmadinejad, president when Iran’s tensions with the West over its nuclear program reached an earlier peak.  

Iranian officials have said Iran has prepared any number of responses, including resuming its nuclear program as before—minus the elements that have been put permanently out of commission, such as the heavy water reactor near the city of Arak.

"If anyone betrays the deal, they should know that they would face severe consequences,” Rouhani warned during a speech late last month. “Iran is prepared for all possible situations.”

Adm. Shamkhani, speaking at a press conference ahead of a trip to Russia on April 24, said abandoning the nuclear Non-Proliferation Treaty which limits a nation’s atomic programs in exchange for the right to pursue peaceful nuclear applications, was one possible response.

"We have put a number of options for ourselves and those options are ready, including options that would involve resuming at a much greater speed our nuclear activities," Zarif told reporters during an April 21 visit to New York. "America never should have feared Iran producing a nuclear bomb, but we will pursue vigorously our nuclear enrichment.”

Iranian officials have rejected reopening negotiations over the Joint Comprehensive Plan of Action or the “better deal” that Trump wants. Far less isolated than in previous years, they speak regularly to top European and Asian officials and likely know how complicated it would be for Trump to get all international parties involved in the deal to reopen talks on a subject that consumed so much diplomatic bandwidth for a dozen years. One of the signal achievements of the Obama administration was to get Russia and China on board for sanctions and the agreement.

Khamenei, Shamkhani, the heads of the IRGC and others also know that Russia, at least, sees Iran as a vital partner in its Middle East ambitions. Russian President Vladimir Putin has shown a willingness to wield its United Nations Security Council veto even on minor matters that affect its partners. For example, Russia on February 26 vetoed a relatively mild U.K.-drafted resolution accusing Iran of violating a Yemen arms embargo.

The Iranians understand that the tough U.N. Security Council sanctions imposed in 2010 that ultimately strangled Iran’s oil-dependent economy and brought it to the negotiating table came about during the brief interregnum when Putin had stepped aside as president and Dmitry Medvedev was at the helm, while the toxic Mahmoud Ahmadinejad was president of Iran, and the charismatic Obama was U.S. president. Such a geopolitical alignment of stars eludes Trump.

On May 12, when the Trump administration may fail to recertify the nuclear deal, Iran will likely want to make an immediate symbolic gesture, perhaps by ramping up enrichment. Iran’s Natanz facility currently is allowed to operate no more than 5,000 of its oldest-model centrifuges, down from a peak f 20,000 before the nuclear deal.

“Maybe some more centrifuges will start spinning,” said Ali Fathollah-Nejad, an Iran expert at the Brookings Doha Center.

But few expect the Iranians to scale up nuclear activities too much or too quickly. Almost all the players at the table at the Supreme National Security Council have significant stakes in the success of the nuclear accord. A 2017 analysis by Reuters showed that most of the new deals signed since the nuclear agreements was reached benefited powerful state and semi-state actors. Any major move by the Iranians would make it very difficult for European governments in Berlin, Paris and Rome to continue defending a deal whose preservation has mostly benefited regime elites.

“They’re not going to react in a major way to piss off the Europeans,” said Fathollah-Nejad.

The weeks and even months after the U.S. gets out of the deal will be crucial: Europeans and U.N. Security Council members will have to offer incentives to keep Iran on board. Zarif, along with Shamkhani, and other Iranian national security officials, has been meeting with foreign officials for months to discuss possible repercussions and responses, according to Western diplomats.

“The response is going to be designed to pressure Europe, Russia and China to step up and defend the deal in a meaningful way,” said Sanam Vakil, an Iran specialist at Chatham House. “I think they will give Europeans a timeline. ‘If you don’t do something by this amount of time, we will do this.’”

Iran has been riven by strife between competing factions since the beginning of the revolution. One reason the Islamic Republic founders created the SNSC after Khomeini’s death in 1989 was to manage the infighting, although it continues to this day.

Many hardliners were opposed to the nuclear deal in the first place, and certainly didn’t want the moderate Rouhani to benefit from it politically.  Although almost all factions have gained from the cash and patronage generated by the Iran deal, a spate of arrests of prominent dual-national Iranians by the Revolutionary Guard has signaled a willingness to scuttle the deal. Further signs of a downturn in an economy already in trouble over its plummeting currency or loss of business after the Trump decision could further empower those players.  

“If Iran doesn't benefit from the deal, it can't stay in it,” said Haghirian, the Tehran-based analyst and researcher. “The government will not be able to convince the hardliners and Supreme Leader to stay unless the Europeans bring very strong incentives to the table.”

That’s why the Trump administration’s decisions on which sanctions to waive and which to re-implement will play a key role in deciding how Europe reacts, and how Iran will respond. Many Iranian officials are skeptical about whether Europe has the wherewithal to stand up to the U.S.

“Iran does not see Europe as being at a level to stand up to America, which is why we will leave the deal if the U.S. quits,” said Hossein Naqavi-Hosseini, spokesman of the Iranian parliament’s National Security and Foreign Policy Commission, another significant center of decision-making on the nuclear program.

Speaking last week, the hardline lawmaker warned that if the U.S. left the deal, the result would be that Iran would ramp up its nuclear program. "Everything will go back to how it was before," he warned.

The day the U.S. scuttles the nuclear deal, Iran’s hardliners, moderates and reformists will put on a grand show of unity— everyone from Denver-educated Zarif to hardline Mohammad Ali Jafaari, the commander of the Revolutionary Guards. They will issue harsh statements about America and its untrustworthiness.  

“We will have the rhetorical warfare coming from all echelons of the regime,” said Vakil, who has studied Iran’s elite. “They’re going to create an edifice of factional unity.” But if the past is any guide, the unity won’t last. Hardliners will eventually begin depicting Rouhani and Zarif as suckers for trusting the U.S., and moderates and reformists will be forced to defend themselves. After anti-government protests over the economy broke out in late December and early January, Rouhani forcefully argued that IRGC and other corrupt elites were to blame for the economy’s sorry state.

Rouhani doesn’t have any veto power over crucial matters of state. But as the twice popularly elected president, his voice at the SNSC carries weight, and he and his supporters have argued that he’s the standard-bearer of the bedraggled Iranian populace. He will argue, probably with success, that any drastic move on the part of the regime would only hurt Iran by further damaging the economy, alienating potential allies and squandering the goodwill built with the international community since Ahmadinejad left office in 2013.

More likely than not, Tehran will move slowly, and deliberately, attempting to gain maximum advantage by incrementally increasing its nuclear program at home while exploiting the Trump administration’s unpopularity abroad and in America. But while Iranian officials are watching closely what’s happening in U.S. domestic politics, they’re not placing any bets on the outcome of November’s midterm elections.

“They’re not going to determine their response based on the possibility that Trump and the Republicans could face a loss at elections,” said Vakil. American domestic politics are “much more important for the Europeans. They’re trying to manage a soft U.S. exit, that would allow the U.S. to come back in at another time.”

That is, even if that time has to wait for the day when Trump is no longer in power.