Prospects of reviving the 2015 nuclear agreement between Iran and the P5+1 — China, France, Germany, Russia, the United Kingdom, the United States — have decreased significantly.

Negotiations on the agreement, officially the Joint Comprehensive Plan of Action (JCPOA), have stalled since September 2022 while Iran's nuclear program continues to advance in a way that renders the JCPOA's technical clauses increasingly redundant.

The Biden administration and Iran are each likely to lose interest as the November 2024 US presidential election approaches. The US will probably not see sufficient political benefit in securing a deal; Iran will likely assess that by that time, any potential economic benefits accruing from the deal's revival risk being reversed by a potential incoming Republican administration.

We consider what a definitive collapse in negotiations between Iran and the P5+1 over the revival of the JCPOA could look like and identify seven tripwires that would indicate that a collapse was becoming more likely. The tripwires are not mutually exclusive; the first four are unlikely to trigger the collapse of talks on their own, but would significantly increase the likelihood by deepening the current impasse.

What a collapse could look like

The JCPOA's collapse, especially if through a deliberate Iranian decision to withdraw, would raise the likelihood of a strike initiated by Israel/the US targeting Iran's nuclear facilities. This would become a very likely scenario if Iran also abandoned the Nuclear Non-Proliferation Treaty (NPT), which would entail the termination of the existing basic surveillance and inspections regime.

Abandoning the JCPOA, and almost certainly the NPT, would also very likely depend on China and Russia not objecting. Although abandoning the NPT would not necessarily imply Iran's decision to weaponize, it would significantly increase the likelihood of Iran being able to do so without early detection, raising the likelihood of preventive strikes.

Iran would be likely to carry out retributive attacks, directly or by proxy, and would probably limit these in geographical scope — mainly towards Israel and US deployments around the region — and duration to avoid degenerating into a broader war that it deemed would jeopardize the Islamic Republic's survival.

However, if Iran's leadership assessed that a military campaign against Iranian territory would imminently expand beyond a limited-scope strike towards destruction of the political establishment and regime change, it would likely be compelled to also expand the scope and impact of its military response.

Seven tripwires

Indicators that a collapse in negotiations was becoming more likely are:

• The US/E3 (the UK, France, and Germany) trigger the sanctions snapback clause contained in UN Security Council Resolution 2231, which endorsed the JCPOA, citing Iran's significant nuclear advancements or sales of advanced standoff weapons to Russia. Resolution 2231 is structured such that any of the P5+1 can invoke sanctions snapback without others, including China and Russia, able to veto the decision.

• The Board of Governors of the International Atomic Energy Agency (IAEA) refers Iran back to the UN Security Council, opening the way for a snapback of international sanctions. Such a decision would likely flow from a joint assessment that Iran was making significant, irreversible nuclear advances, pressing for unrealistic demands including closure of the IAEA probe, and lacked serious intent to reach a deal.

• The civilian death toll continues rising amid Iran's countrywide protests, and Western governments increasingly intensify sanctions on Iranian authorities and support the emergent Iranian "leadership" collective in exile.

• Iran further increases its uranium enrichment levels beyond the current 60% fissile purity up to 90% (military grade). Deliberate enrichment to military grade is no longer necessarily a "red line" that would trigger an Israeli or US military campaign targeting Iran's nuclear facilities but, along with conversion into metal form, would further reduce the benefits for the US/E3 in preserving the JCPOA.

• Iran further downgrades or categorically curtails cooperation with the IAEA, removing inspectors and remaining surveillance cameras. 

• Israel, the US, or other allied governments reach an assessment that Iran has taken the decision to resume weaponization work, which would likely still require one to two years to produce a functioning nuclear device, according to US and Israeli estimates.

• Israel and/or the US initiate a strike on Iranian military/nuclear targets because of Iran's nuclear advances or in response to an Iranian attack involving large numbers of US or Israeli fatalities. A strike on Iran's nuclear facilities is very unlikely while negotiations have not definitively collapsed.

This article was published by S&P Global Market Intelligence and not by S&P Global Ratings, which is a separately managed division of S&P Global.