US President Joe Biden’s foreign policy credentials have long been questioned by critics on both the left and the right of US politics who contend that his record is littered with bad decisions. On assuming office, Biden inherited a toxic foreign policy legacy from Donald Trump’s administration, but so far he has had mixed success in remedying the damage.

Biden’s decision to proceed with his predecessor’s Afghanistan plan and his inept management of the withdrawal have confirmed the concerns of Biden’s critics.

The US’s NATO allies, blindsided and exposed by Washington’s thief-in-the-night withdrawal, are now questioning whether America is a reliable partner. And its adversaries—both state and non-state—smell blood and will be looking to capitalise on the symbolism of an apparent US defeat in Afghanistan and the ineptitude of Washington’s strategic policy establishment.

But Biden still faces an even more significant foreign policy legacy from the Trump era that remains unresolved—the moribund 2015 Joint Comprehensive Plan of Action (JCPOA) on Iran’s nuclear program.

To Biden’s credit, his administration has devoted considerable effort to negotiating with Iran on a return to the JCPOA. Initially, there were positive signs that Washington was prepared to make the necessary first step towards renewing the agreement by instituting a broad rollback of many US sanctions on Iran. But negotiations stalled due to recalcitrance and prevarication on both sides.  Critically, Biden failed to take advantage of the last six months and seal a renewed agreement with a relatively moderate Iranian administration under Hassan Rouhani, who has since been replaced as president by the more hardline Ebrahim Raisi.

Commentary from Washington in recent weeks suggests that the prospects for a renewed nuclear agreement with Iran are becoming increasingly remote. Iran’s nuclear program has also now reached two milestones that suggest that if it hasn’t already passed the point of no return, it soon will.

In mid-June, Tehran claimed that it had 6.5 kilograms of uranium enriched to 60%, with a further 108 kilograms enriched to 20%. This indicated that Tehran was well on the way to hitting the 90% enrichment threshold required for weapons-grade uranium. And in mid-August, reports emerged that the International Atomic Energy Agency had verified that Tehran had fabricated 200 grams of uranium metal enriched to 20%, a key step in producing a nuclear bomb.

Since 2018, Tehran has clearly made progress with its capacity to enrich uranium to the level required for a nuclear bomb. But critically, it has also continued to publicise milestones in its nuclear program. This is significant because it suggests that Tehran is still pursuing a nuclear escalation strategy intended to force the US to relax sanctions and return to the JCPOA without conditions, and is not necessarily pursuing a final sprint towards a nuclear weapons capability.

Tehran has also made it clear on multiple occasions that its return to compliance with the JCPOA can be achieved by the US providing sanctions relief. It reiterated this position in mid-August, commenting, ‘If the other parties return to their obligations under the nuclear accord and Washington fully and verifiably lifts its unilateral and illegal sanctions ... all of Iran's mitigation and countermeasures will be reversible.’

Importantly, Iran’s new president has inherited a litany of challenges that may make his administration more open to compromise. These include a collapsing economy, a coronavirus-fuelled public health crisis and protests in the drought-ravaged Khuzestan province, home to Iran’s restive Ahwaz Sunni Arab population. The return of the Taliban in Kabul also poses a significant strategic threat to Iran and will be viewed with considerable trepidation by Tehran. As noted by Shlomo Ben-Ami, former foreign minister of Israel, a new nuclear agreement is an existential imperative for Iran and now might be as good a time as any for Washington to get a lasting agreement.

However, Biden must avoid the temptation to exploit Iran’s current vulnerability by perpetuating Trump’s disastrous ‘maximum pressure’ strategy or imposing new conditions on Tehran. He should also dispense with any demands to include additional elements in a renewed agreement, such as clauses committing Iran to further talks on its ballistic missile program and its support for Shia proxy militias across the Middle East. These conditions risk placing negotiations on a path to failure.

Biden must also accept that it was Washington, not Tehran, that killed off the JCPOA in 2018. If this means that the US must pay a higher price for Iran’s return to the terms of the agreement, then it should. Washington may not be able to agree to Tehran’s impossible demand for a guarantee that future US administrations won’t be able to renege on a new deal. But it should offer separate discussions with Tehran on waiving all non-nuclear sanctions. While this may not satisfy Tehran’s demands initially, if delivered with a commitment to unconditionally and immediately waive all nuclear-related sanctions reimposed by Trump, it may get negotiations back on track. It would also put the ball back in Iran’s court.

Any concessions Biden makes to Iran will be savaged by his critics in Washington and condemned by opponents of the JCPOA in Israel and Saudi Arabia. But he has more to gain from such an act of good faith than he has to lose. His administration is heading towards another catastrophic foreign policy failure that may lead to another war in the Middle East. The risk that Israel will take matters into its own hands by launching a military strike against Iranian nuclear facilities increases the longer negotiations drag on. Such an attack would ultimately prove self-defeating.

The Trump administration’s withdrawal from the JCPOA was a catastrophically bad idea that made an Iranian nuclear bomb more likely, not less. Should Biden fail to breathe life into the JCPOA, he will again share the blame with Trump for whatever comes next. But if Biden can get the JCPOA back on track, he will have achieved more than just recommitting Tehran to the terms of the deal. He may have prevented another war. He will also have demonstrated to the other parties to the JCPOA that Washington is again a reliable partner and shown that there is still a place in foreign policy for unilateral acts of good faith.