In a recent analysis ^[1], Richard Haass suggests that one way out of the current crisis with Iran is a renegotiated Joint Comprehensive Plan of Action (JCPOA) that addresses shortcomings in the 2015 Iran nuclear deal negotiated by the Obama administration alongside France, the UK, Germany, China, Russia and the EU.

The original JCPOA ^[2] is flawed because it doesn’t ultimately prevent Iranian nuclear acquisition in the long term. It’s scheduled to ‘sunset’ over the 2026–2031 period as various constraints on Iran’s nuclear ambitions are lifted. The risk is that Iran could remain in full compliance with the JCPOA but exploit easing constraints over time, so that, as the agreement lapses, Tehran is well placed to make a quick breakout ^[3] towards acquiring nuclear weapons. In this sense, the JCPOA may ultimately not  solve anything beyond kicking the can down the road, in much the same way that numerous failed agreements with North Korea have done.

Nor does the current JCPOA deal with Iranian ballistic-missile development ^[4]. Tehran has been free to develop delivery systems for nuclear weapons and to modernise its ballistic missile technology. By the time the agreement expired, Iran’s ballistic-missile capabilities would likely be significantly more advanced than they are now ^[5].

Furthermore, from about 2023, the JCPOA allows Iran to acquire advanced military capabilities. A mere three and a half years from now, Russia and China could be pounding on the doors of Iran’s defence ministry offering the latest capabilities at highly competitive prices. By the late 2020s, Iran could have modernised its military forces and developed more advanced ballistic missile capabilities with longer range. Iranian nuclear weapons by the early 2030s would then be the icing on the cake.

The geopolitical assumptions underpinning the JCPOA negotiations were also dubious. I argued in 2017 ^[6] that it was based on a strategy of hope. The hope was that somehow, through good intentions on the part of the West led by the US, an arms-control approach to Tehran would change Iran’s strategic calculus and mindset, and it would willingly forgo nuclear weapons and become a responsible regional actor. Yet, since the signing of the JCPOA, Iran’s expanding presence ^[7] in Syria ^[8], poised against Israel’s northern border; its ongoing support for terrorist groups such as Hezbollah ^[9] and Hamas; and its expanding influence in Iraq ^[10] don’t support such an optimistic hypothesis.

And now Tehran has reportedly attacked ^[11] commercial shipping in the Persian Gulf and, in an unprovoked attack, has apparently shot down a US RQ-4A Global Hawk drone in international ^[12] airspace. At the same time, Iran is moving towards increasing ^[13] its production of low-enriched uranium production to a level that will exceed the limits of the JCPOA in coming days, and has indicated it may enrich uranium to a higher level. That step would allow a shorter breakout time for acquiring nuclear weapons. An Iranian scramble for a bomb could prompt US or Israeli preventive strikes and increase the risk of proliferation cascades ^[14] with Saudi Arabia ^[15] and other regional actors.

Certainly, an argument can be made that Tehran is responding to the US’s withdrawal ^[16] from the JCPOA in 2018 and the reintroduction of sanctions. The blame can be shared around, and the Trump administration would have been wiser to have stuck with the JCPOA, with all its flaws, and proposed side agreements to close its loopholes. By pulling out of the JCPOA, the US has effectively assumed the blame for the current crisis and has handed a political victory to Tehran for nothing in return. Iran is now set to walk away from the deal too, and that will add a new level of risk to the mix.

Two possible paths forward seem to be emerging. The first is an escalatory cycle of action–reaction between Iran and the US, leading to some form of military conflict in the near future. Further Iranian attacks on shipping, for example, would accelerate the slide towards war. Such attacks would be an unacceptable breach of international legal norms upholding freedom of navigation of the seas. The US would be correct to defend commercial shipping against future attacks, even at the risk of further provocations from Iran.

There’s no indication yet that the US is actively preparing for war with Iran, and President Donald Trump doesn’t seem eager ^[17] to embark on such a conflict. It’s unclear ^[18] what war would really achieve, or what the objectives of the US, and any coalition partners, would be. Limited military strikes on Iranian nuclear facilities are not likely to force Iran to give up any future nuclear ambitions and would almost certainly prompt Iranian ^[19] retaliation ^[20] against the US throughout the region—for example, via state-sponsored militias in Iraq or via naval units of Iran’s Islamic Revolutionary Guard Corps in the Persian Gulf. The US would respond in turn, and the risk is of an escalating conflict drawing the US deeper into a quagmire ^[21] that would be longer and worse than Iraq and Afghanistan.

Nor would it be likely to lead to regime change in Tehran. The potential cost in lives would be immense. The US would be further isolated from its partners in Europe, who are unlikely to support the Trump administration in such a conflict. It seems highly unlikely that the US would gain a legal mandate beyond self-defence, and no chapter VII UN Security Council authorisation would be forthcoming.

The larger geopolitical canvas also matters, and in the event of a prolonged US–Iran war, the US would be distracted from responding to the much more serious risk of an assertive China and a revanchist Russia. Beijing and Moscow are increasingly coming together to challenge US strategic primacy and the Western alliance system and to bring about a revised rules-based international order that ends US global leadership. So while the US must respond to provocation, a new war isn’t going to end happily for anyone.

A better alternative is to test Tehran’s intentions. A new Iran deal of the sort that Haass argues for—a ‘JCPOA 2.0’—should be proposed. The objective from the US side should be to close loopholes in the original deal to truly preclude Iranian acquisition of nuclear weapons over a much longer period, and sweep up Iranian ballistic-missile development in a way that caps, and then rolls back, such capability. In return for Iran’s agreement, and through adequate verification and monitoring by the International Atomic Energy Agency, sanctions would be eased, allowing the original JCPOA’s trade benefits to flow.

If Tehran would be willing to look at a new deal that really did close off its nuclear option for the long-term—if it really is sincere about not wanting nuclear weapons—it should be willing to talk. That could generate a new opportunity for diplomacy that could ease tensions in the region and allow both sides to pull back from the brink. The likelihood is, though, that they won’t.