Iran's conservative-dominated parliament passed a bill on Tuesday approving its nuclear deal with world powers, signalling victory for the government over hardline opponents who worry the accord opens a door to wider rapprochement with the West.
Many conservative lawmakers opposed the Joint Comprehensive Plan of Action (JCPOA) that President Hassan Rouhani's government agreed with the six powers on July 14, and the vote -- which followed a bad-tempered, rowdy debate on Sunday -- lifts a significant hurdle to putting the deal into effect.
With strong parliamentary backing, the bill is likely to be ratified by a clerical body called the Guardian Council.
The exact stance of Supreme Leader Ayatollah Ali Khamenei, who has the last word on all matters of state, is not known. To date, he has neither approved nor rejected the agreement, but has commended the work of Rouhani's negotiating team.
Provided Khamenei does not openly oppose it, many expect Iran will begin shutting down parts of its nuclear program in coming weeks. When completed, that process will result in most international sanctions, imposed on Iran since 2006 over concerns it was covertly seeking atomic bombs, being lifted.
The bill also calls on Iran's government to impose strict curbs on U.N. nuclear inspectors' access to military sites, leaving the possibility that disagreements could still arise.
"Members of parliament made a well-considered decision today showing they have a good understanding of the country's situation," government spokesman Mohammad Baqer Nobakht said in a televised news conference after the vote.
The bill was adopted with 161 votes in favor, 59 against and 13 abstentions, the state news agency IRNA said. It had passed a preliminary vote on Sunday by a smaller margin, after a chaotic debate in the 290-seat chamber.
State television froze its live video coverage of Sunday's debate as tempers frayed. Nuclear agency chief Ali Akbar Salehi could be heard shouting "listen, listen!", his voice turning hoarse as he struggled to be heard over dissenting roars.
Iranian agencies, which witnessed the debate, reported that Salehi came under physical assault as he addressed the chamber, while a lawmaker opposed to the motion was admitted to hospital with heart problems linked to stress after losing Sunday's vote.
The bill will now be submitted to the Guardian Council, a clerical vetting body, that will either suggest amendments to the text or pass it into law.
A spokesman told Tasnim news agency that the council, six of whose 12 members are appointed by Khamenei and the rest by parliament, would return its verdict by Thursday if given the draft on Tuesday.
"Most policymakers expect this to pass quite quickly and smoothly. The Guardian Council's framework is such that, if the JCPOA has reached this stage, it is highly unlikely to derail it now," said Ellie Geranmayeh, policy fellow at the European Council on Foreign Relations.
She added that Khamenei was now likely to support Rouhani's government in carrying out the deal, while also highlighting parliament's insistence on limiting access to military sites for International Atomic Energy Agency inspectors.
The bill stipulates that inspectors from the IAEA, the U.N. nuclear watchdog, cannot visit such sites without approval from a top Iranian security organ.
Conservative hardliners, including Khamenei, fear Western powers aim to use transparency required by the nuclear deal to access Iran's state secrets, or that it will usher in a detente with the West harmful to Iran's 1979 Islamic Revolution.
On Oct. 7, however, Khamenei appeared to put the brakes on moderates hoping the deal will end Iran's isolation by banning any further negotiations between Iran and the United States, contradicting expectations voiced by Rouhani.
For their part, Western critics of the agreement say that it is not tough enough to prevent Iran eventually perfecting the ability to build an atomic bomb with enriched uranium.
Ingrained mutual mistrust could cause delays in the implementation of the nuclear deal and provoke further heated debate both in Iran and the United States, where opposition conservative Republicans lost a battle to torpedo the accord in Congress, but is unlikely to derail it altogether, analysts say.
"There is a process within the JCPOA to manage any disputes that arise... it's too early to say that (the question of military access) is going to cause a crisis," Geranmayeh said.
The IAEA wants to be able to visit military sites if it deems this necessary to verify that Iran's nuclear program is wholly for the purpose of peaceful energy as Tehran asserts.
The draft law also called on the armed forces and the government to continue developing Iran's military power, suggesting the Islamic Republic will maintain its active role in Middle Eastern conflicts such as Syria, where its interests have clashed with those of Western and Gulf Arab powers.
On Sunday, Iran tested a new precision-guided ballistic missile, the first such weapon able to reach its regional arch-enemy Israel, defying a U.N. resolution that bans Iran from developing missiles that could deliver a nuclear warhead.
The draft bill also says Iran should resume all nuclear activity that it would halt as part of the deal, if the other side fails to meet its obligations to lift sanctions.
Under the July 14 deal with the United States, Britain, France, Germany, Russia and China, Tehran accepted strict limitations on its uranium enrichment program in exchange for relief from the sanctions that have crippled its economy.
Iran is due to start implementing the deal on October 18 or 19, known as Adoption Day under the terms of the JCPOA. Iranian technicians will decommission thousands of the centrifuges that refine uranium, fill the Arak heavy water reactor with concrete and ship most of Iran's stockpile of enriched uranium abroad.
Once the IAEA is satisfied Iran has met its obligations, which Tehran hopes to achieve by early 2016 but could take longer, the United States, United Nations and European Union will rescind nuclear-related sanctions.
Some U.S. sanctions not related to the nuclear file will remain in place, but that has not deterred foreign business delegations that have flocked to Tehran ahead of the expected opening of markets in the oil-rich nation of 80 million people.