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In the days after President Trump pulled the United States out of the Iran nuclear deal, it seemed that maybe — just maybe — the accord could be saved. European officials pledged to salvage the arrangement, even if that meant negotiating new financial incentives for Tehran to stay in the pact. Iran, meanwhile, said it would continue to limit its enriched-uranium production and allow international inspectors inside the country.

But Tehran's willingness to stay the course seems to be wearing thin.

On Sunday, Iran's foreign minister called on his European counterparts to stand up to Trump and “make up for Iran's losses.” Days later, the country's supreme leader, Ayatollah Ali Khamenei, said that Europe's current efforts do not go nearly far enough to justify keeping the deal in place.

“The Europeans expect the Iranian nation to tolerate and grapple with the sanctions, to give up their nuclear activities, which is an absolute requirement for the future of the country, and also to continue with the restrictions that have been imposed on them,” he said. “I would tell these governments that this bad dream will not come true.”

Iran's supreme leader, Ayatollah Ali Khamenei, waves to supporters March 21 in Mashhad, Iran. (Office of the Iranian Supreme Leader via AP)

Perhaps the most telling move came Tuesday, when Iran began to tiptoe back toward building up its nuclear capabilities.

Iranian officials announced that they have begun work on a new centrifuge-assembly center at the Natanz nuclear site. Natanz is Iran's largest nuclear facility; it began operating in 2007 in violation of U.N. efforts to stop the country's uranium-enrichment program because of proliferation concerns. Natanz is capable of producing low-enriched uranium, which can be used as fuel by civilian nuclear reactors to generate electricity. But concerns have been raised that the facility could also be used to enrich uranium to a much higher level, to about 90 percent purity, or the “weapons-grade” level needed for the fissile material of a nuclear bomb.

So far, Tehran has kept its promise to maintain its enrichment program within the limits of the 2015 nuclear accord, which required Iran to sharply reduce its enriched-uranium stockpiles and to restrict enrichment to less than 4 percent concentration — far below what is required to make a nuclear weapon. But experts say that building the new center at Natanz is a shot across the bow, an indication that Khamenei was serious when he threatened to step up enrichment if the deal fell apart.

“This is a clear signal from Tehran that it is not simply a bystander and that if the nuclear deal collapses, it has options too,” wrote the BBC's Jonathan Marcus.

Ali Vaez, who leads the Iran Project at the International Crisis Group, says he thinks that Iran's announcement is not in itself an indication that the Iranians want to pull out of the deal. To him, it is a carefully calibrated way for Iran to signal its seriousness about restarting suspended elements of its nuclear program without violating the terms of the accord. But that could change.

“There is a tipping point beyond which politically it becomes unsustainable,” Vaez said — and that point may be fast approaching.

European officials are struggling to come up with a package of incentives that will appeal to Tehran. The nuclear accord afforded Iran tremendous opportunities to enter the global market, but Trump's decision to reimpose sanctions makes it much harder for the country to reap those much-needed economic benefits.

In particular, it is hard to imagine how Iran's European allies will be able preserve Iran's access to oil markets and the global financial system, both of which depend heavily on the United States. As Reuters explained, “they are struggling to convince firms to remain in Iran or create the financial instruments that could even enable them to do so.”

Several businesses have already pulled out, including General Electric and French auto giant Groupe PSA, which makes Peugeot and Citroen cars. In 2017, the group produced 440,000 vehicles in Iran, but PSA has begun to close its joint ventures with local carmakers. (The group says it will seek a sanctions waiver from the United States.)

At the same time, Iran's enemies are circling. Israeli Prime Minister Benjamin Netanyahu said this weekend that Iran's threats to increase its uranium-enrichment capacity show that the country still wants to destroy Israel. Netanyahu urged his European allies to abandon the accord.

The combined economic and political pressures are likely to make it hard for Iran's moderates to convince Iranians that remaining in the deal is in their best interest.

“It's likely that Iran will still grow significantly more economically isolated than it has been over the past two years,” Peter Beinart wrote in the Atlantic. “In the run-up to Trump’s withdrawal announcement, the value of Iran’s currency, the rial, plunged, sparking fears of hyperinflation. This predictably has played into the hands of pro-regime conservatives, who have responded by vowing to build a 'resistance economy' dominated by the state.”

The Iranian president may be able to maintain power only if he bows out of the deal. As my colleague Ishaan Tharoor put it, “it seems increasingly unlikely that Iranian President Hassan Rouhani — who championed diplomacy with the West — will be able to resist calls from his country's hard-liners to also renege on their end of the bargain.”

But if Iran pulls out and faces yet more sanctions from the United States and its allies, it will not be bad just for Iranians. Sanctions have a way of neutering movement toward democracy, rewarding radicals and dictators and silencing dissent.

Reinstating sanctions, in the words of Columbia University’s Richard Nephew, who worked on Iran sanctions and negotiations for President Barack Obama, “is an opportunity to restrict access to the country and by people in the country to the outside world. This concept of economic resistance is very attractive to them, as they see that openness can damage and undermine their control.”

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