Iran’s nuclear program has driven US‑Iran tensions for more than two decades. Washington accuses Tehran of pursuing nuclear weapons; Iran denies this and insists on a civilian nuclear right. US President Donald Trump has said stopping Iran from acquiring a nuclear weapon was a key reason behind the US decision, together with Israel, to attack Iran on February 28. A ceasefire is now in place, and negotiations between the two sides could soon resume.
Back to 2015?
More than 10 years ago Washington and Tehran reached a landmark compromise. The 2015 nuclear agreement, the Joint Comprehensive Plan of Action (JCPOA), aimed to curb Iran’s nuclear program in exchange for sanctions relief. It collapsed after the US withdrew in 2018.
Trump, who left the deal during his first term, has repeatedly argued he could secure a “better” agreement than the one negotiated under President Barack Obama. The question is whether a new deal can realistically go further — or whether diplomacy today is operating under far worse conditions than in 2015.
What did the 2015 nuclear deal achieve?
After 20 months of talks, Iran and world powers reached an agreement in July 2015. The JCPOA significantly slowed Iran’s ability to produce enough fissile material for a weapon — its “breakout time” — from about two to three months to roughly a year. The deal gave the International Atomic Energy Agency (IAEA) broad access to inspect Iran’s nuclear facilities and lifted international economic sanctions once the IAEA confirmed compliance in January 2016.
“The IAEA did get unprecedented access,” said Oliver Meier, a nuclear disarmament expert at the European Leadership Network. “It limited the number of centrifuges and the types of centrifuges Iran was using, and it reduced the stockpiles of fissile material inside Iran.” Meier added that many restrictions were time‑bound, set to expire after 10 or 15 years, assuming international confidence would be rebuilt.
What the deal did not cover
The JCPOA left clear gaps. It did not restrict Iran’s ballistic missile program or address Tehran’s role in regional conflicts, including support for groups such as Hezbollah. “There was a conscious decision at the time to leave out certain aspects that, in hindsight, might have been better tackled,” Meier said. Critics argued the deal postponed rather than eliminated the nuclear threat and failed to curb Iran’s broader strategic ambitions.
When Trump took office in 2017 he called the JCPOA “the worst deal ever negotiated” and withdrew the US a year later, reimposing sweeping sanctions with the aim of forcing Iran to accept broader, tougher terms.
From failed diplomacy to war
Iran initially stayed within the deal, hoping the remaining signatories could offset US sanctions. Over time Tehran scaled back commitments, enriching uranium to higher levels, deploying more advanced centrifuges and reducing cooperation with inspectors. “The outcome was unfortunately that Iran’s breakout time was considerably shortened,” Meier said. By 2024 the IAEA estimated the timeframe had fallen to weeks or even days, though there was no clear evidence Iran had decided to build a bomb.
Efforts to revive or replace the JCPOA continued into 2025 and 2026 but collapsed after the February 28 offensive by the US and Israel, which triggered Iranian counterattacks on Israel and US allies in the Gulf. After 40 days of fighting the US and Iran agreed to a ceasefire on April 8. Negotiations are set to resume in Islamabad against this troubled backdrop.
What’s on the table now
The central dispute is time. The US is demanding a 20‑year suspension of Iran’s nuclear activities; Iran says it will accept restrictions for up to five years. Other unresolved questions include who would monitor Iran’s facilities, what would happen to its enriched uranium stockpile, and how many centrifuges Iran could keep. “The issues that need to be resolved now are, not surprisingly, the same ones the 2015 deal addressed,” Meier noted, and he is skeptical a solution can be found in days or weeks.
Why US‑Iran talks are harder this time
Many experts say the JCPOA was possible because a basic level of trust still existed between the parties; today that foundation has largely disappeared. Alan Eyre, who was part of the 2015 US negotiating team and is now at the Middle East Institute, said positions have hardened and “there’s a tremendous amount of distrust and suspicion on the American side towards Iran and on the Iranian side toward the United States.”
Eyre added Iran has regained strategic leverage. Despite heavy wartime losses, Tehran can still retaliate with missiles, rockets and drones, threaten shipping through the Strait of Hormuz and rely on regional proxies such as Hezbollah and the Houthis — leverage it lacked in 2015. He also said the current US administration shows a lack of diplomatic expertise and questioned whether negotiators like JD Vance could match Iran’s experienced negotiating teams. Former negotiators stress that experience and trust matter as much as leverage.
So, can Trump still get a better deal than Obama?
In one sense the answer could be yes. “It will be easier to get a better deal in the sense that many nuclear facilities have been destroyed,” Meier said. Iran may be more willing to accept that some sites are no longer on the table.
Politically, however, the situation is far more complicated. “We are in a much worse place than in 2015,” Meier said. “The attacks have not solved the problem. They have made it worse, because more people in Iran now believe a nuclear weapon is needed to deter future US attacks.” That has made long‑term limits harder to achieve.
As Washington and Tehran consider another attempt at diplomacy, the question is no longer just whether a better deal is possible — but whether the conditions that made the 2015 agreement work can be recreated at all.
Edited by: Don Mac Coitir