Why is the US so determined to extend a UN arms embargo on Iran, and will it work?
The UN Security Council is preparing to vote this week on a US proposal to extend an arms embargo on Iran, a move that some diplomats say is bound to fail.
'I am confident that ... members of the Security Council will refute the campaign struggle of a beleaguered US administration to turn what was the diplomatic achievement of the 21st century into an exercise in futility'
- Iranian Foreign Minister Mohammad Javad Zarif
Still, US Secretary of State Mike Pompeo seems certain that Washington will get its way, insisting during an interview on Wednesday that the United States was "determined to make sure" the embargo extension happens.
Pressure from Washington, including the reinstatement of strict sanctions, has put an already fragile nuclear deal between Tehran and world powers at further risk.
But what is the arms embargo, and why is the US so determined to stop the measure from expiring in October?
From the beginning
The United Nations Security Council imposed an arms embargo on Iran in 2007, but when world leaders penned the multilateral Iran nuclear deal in 2015, a five-year sunset clause on the embargo was negotiated, setting the October 2020 expiration date.
The agreement relied upon Iran's compliance with the nuclear deal. If Iran was found to be non-compliant, any signing member of the agreement would be able to request a mediation or a "snapback" of sanctions, including the arms embargo.
If this week's Security Council motion is vetoed, Washington plans to use that nuclear agreement measure to snap back sanctions. Still, the US, one of the original signatories, withdrew from the nuclear deal in 2018 under the leadership of US President Donald Trump, who dubbed it "the worst deal ever".
The remaining signatories - Russia, China, Germany, Britain, France and Iran - have argued that the US gave up its right to trigger a snapback motion when it withdrew from the deal.
Will Iran become 'a rogue weapons dealer'?
The Trump administration has been particularly hawkish towards Iran and accuses the Islamic Republic of being a state sponsor of terrorism and meddling in conflicts throughout the Middle East, including in Yemen and Syria, and beyond.
Pompeo said in June that if the embargo were to be lifted: "Iran will be free to become a rogue weapons dealer, supplying arms to fuel conflicts from Venezuela, to Syria, to the far reaches of Afghanistan."
Iran has rejected Washington's accusations.
Europe has acknowledged the nuclear deal is not working as planned, primarily because of Washington's "maximum pressure" sanctions campaign, but has expressed more interest in mediation than in the reinstatement of international sanctions.
Meanwhile, the US has highlighted support from Iran's neighbours, with Pompeo saying on Wednesday: "Look at the countries closest to it. Look at the Arab countries. They’re all in support of the arms embargo extension. Look at Israel. They’re in support of it."
Russia and China, two powerful Security Council members, however, are not on board.
Why are Russia and China opposed to extending the arms embargo?
Iran's two strongest allies argue that Washington has no legal basis for pushing the Security Council to extend the embargo. They say the 2015 council resolution enshrining the nuclear deal - and the arms embargo and its expiration - should be implemented.
Russian Foreign Minister Sergey Lavrov said in May: "The United States must recognise that there are neither legal nor other grounds for its policy of using Security Council mandates to pursue its own selfish interests."
Washington says Russia and China want to sell weapons to Iran when the embargo expires. The expiration of the deal would open the door for them to do so.
What does this mean for the 2015 nuclear deal?
Diplomats have warned that Washington's plans to trigger the so-called sanctions snapback process at the Security Council would be messy, particularly since the remaining parties to the nuclear deal oppose the move.
It could ultimately kill the nuclear deal because Iran would lose a major incentive for limiting its nuclear activities.
Since Washington quit the deal it has imposed strong unilateral sanctions, and in response, Iran has breached parts of the agreement, which has concerned European signatories - just not enough to reinstate sanctions. Instead, Germany, Britain and France are seeking measures more likely to salvage the deal.
Iran's Foreign Minister Mohammad Javad Zarif on Tuesday described the next few weeks and months as "critical".
"I am confident that ... members of the Security Council will refute the campaign struggle of a beleaguered US administration to turn what was the diplomatic achievement of the 21st century into an exercise in futility," he said.
What sanctions would 'snap back'?
A snapback of UN sanctions would require Iran to suspend all nuclear enrichment-related and reprocessing activities, including research and development, and ban imports of anything that could contribute to those activities, or to the development of nuclear weapon delivery systems.
It would reimpose the arms embargo, ban Iran from developing ballistic missiles capable of delivering nuclear weapons and reimpose targeted sanctions on dozens of individuals and entities. States would also be urged to inspect shipments to and from Iran and authorise them to seize any banned cargo.
Last month, departing US envoy to Iran Brian Hook made it clear that Washington would be willing to use military force as a means to stop Tehran from obtaining nuclear capabilities if it were to try and do so.