Washington's concerns with the Iran nuclear deal

Under US President Donald Trump, Washington's doubts about the virtues of the 2015 Iran nuclear deal have risen back to the surface of policy debate.

The accord still has many fierce supporters, particularly among veterans of Barack Obama's former administration, but the views of anti-Iran hawks have gained ground.

Washington's European allies and even some of Trump's most senior American advisers still think the deal is the best way to curtail Iran's nuclear ambitions.

But Trump's willingness to cast aside Washington foreign policy orthodoxy and denunciate the accord as an "embarrassment" have opened space for counter arguments.

These are the main concerns of the deal's critics:

- The 'sunset clause' -

For US Secretary of State Rex Tillerson, the relatively short timeframe of the accord is its most "glaring flaw."

From 2025, technical controls on Iran's ability to refine nuclear fuel will begin to fall away. Deal critics fear that will leave Iran on the threshold of building a bomb.

Even French President Emmanuel Macron, who wants the underlying deal preserved at all costs, admits that the "sunset" should be addressed in a supplemental accord.

- Limited inspections -

Washington's outspoken ambassador to the UN, Nikki Haley, has pushed hard on the question of inspections by the International Atomic Energy Agency (IAEA).

The UN watchdog is responsible for reporting to the signatories of the deal -- Iran and six world powers -- on whether Tehran is in technical compliance.

So far, it has confirmed that it is, apart from a small number of infractions that have been remedied, but Haley has suggested Iran is barring access to secret sites.

Iran has refused to allow access to military bases not declared as part of its nuclear program, but the US has not provided evidence that Tehran has a covert operation.

- Deal 'too big to fail' -

Another Haley turn of phrase, this encapsulates the idea that the Obama administration was so concerned to preserve the deal that it refused to press Tehran on its other sins.

And by reopening economic and financial ties, the deal created potential costs in terms of lost contracts for European banks and exporters if it was to collapse.

Thus nervousness about offending Tehran and collapsing the accord has made the West reluctant to call out Iranian meddling in Syria, Yemen, Iraq and Lebanon, hawks argue.

- Rocket men -

Architects of the accord insist today that it was only meant to halt Iran's nuclear program, even if some then sold it as part of a rebalancing of Middle East ties.

So it does not tackle Iran's ballistic missile program, which continues apace, despite separate US Security Council sanctions and condemnations.

"The JCPOA represents only a small part of the many issues that we need to deal with when it comes to the Iranian relationship," Tillerson recently said of the accord.

"And I've said many times we cannot let the Iranian relationship be defined solely by that nuclear agreement."

UN Security Council resolution 2231 adopted the Joint Comprehensive plan of Action (JCPOA) into international law, but went further, calling on Iran "not to undertake any activity related to ballistic missiles designed to be capable of delivering nuclear weapons."

Washington therefore argues that even if the JCPOA did not deal with the ballistic threat, UN members intended a missile ban to be within the "spirit" of the broader deal.

- Regional troublemaker -

The spirit of the deal, Trump's administration argues further, was that it would not only halt Iran's nuclear ambition but stop it from destabilizing its neighbors.

The preamble says the signatories "anticipate that full implementation of this JCPOA will positively contribute to regional and international peace and security."

Supporters of the deal insist the preamble is not legally enforceable, but Tillerson and other US officials have cited it to criticize Iran's ongoing subversive role.