Iran’s nuclear program has been a focus of tension between the US and the Islamic Republic for more than two decades. Washington has said that Tehran is working towards developing nuclear weapons, which it wants to stop at all costs. Iran denies seeking the bomb, but insists on its right to a civilian nuclear program.
US President Donald Trump has said that preventing Iran from acquiring nuclear weapons was a major reason behind America’s decision to attack Iran along with Israel on February 28. The ceasefire is now in place and talks between the two sides may resume soon.
Back in 2015?
More than 10 years ago, Washington and Tehran reached a historic agreement. The 2015 nuclear deal, officially known as the Joint Comprehensive Plan of Action (JCPOA), was designed to curb Iran’s nuclear program in exchange for sanctions relief. It collapsed after America’s withdrawal in 2018.
Trump, who pulled the US out of the agreement during his first term, has repeatedly argued that he could secure a “better” deal than the one negotiated under President Barack Obama. The question is whether a new agreement can realistically move forward – or whether diplomacy is being conducted today under even worse conditions than in 2015.
What was achieved by the 2015 nuclear deal?
After 20 months of negotiations, Iran and the US reached an agreement in July 2015 with Russia, China and the European Union led by France, Germany and the United Kingdom, which was still a member state at the time. The deal slowed Iran’s ability to produce enough fissile material for a nuclear weapon from about two to three months to about a year, known as “breakout time”.
The JCPOA also gave the UN nuclear watchdog, the International Atomic Energy Agency (IAEA), broad access to inspect Iran’s nuclear facilities. In return, international economic sanctions against Iran were lifted. The agreement entered into force in January 2016 after the IAEA confirmed Iran’s compliance.
“The IAEA got unprecedented access,” said Oliver Mayer, an expert on nuclear disarmament at the European Leadership Network. “It limited the number and types of centrifuges that Iran could use, and it reduced the stockpile of fissile material inside Iran.” Centrifuges enrich uranium by spinning uranium gas at high speed.
However, Meyer said, “It was all time-bound. Some of the sanctions were supposed to expire after 10 or 15 years, assuming international confidence would have been rebuilt by then.”
What was not included in the deal
The JCPOA also had clear limitations. It did not restrict Iran’s ballistic missile program, nor did it address Tehran’s role in regional conflicts, including its support for groups such as Hezbollah in Lebanon.
“A conscious decision was taken at that time to leave out certain aspects that could have been better dealt with later,” Meyer said. “The hope in 2015 was that once the nuclear issue was resolved, it would be easier to deal with regional security. That may have been a mistake.”
These gaps prompted criticism in the US. Opponents argued that the deal postponed rather than eliminated the nuclear threat and failed to curb Iran’s broader strategic ambitions.
When Trump first came to power in January 2017, he called the JCPOA “the worst deal ever” and withdrew the US a year later. His administration reimposed broad sanctions, arguing that economic pressure would force Iran to accept a broader and tougher deal.
From failed diplomacy to war
Iran initially remained within the agreement, hoping that the remaining signatories could offset US sanctions. However, over time, Tehran began to reduce its commitments. It enriched uranium to higher levels, installed more advanced centrifuges, and reduced cooperation with inspectors.
“Unfortunately the result was that Iran’s breakout time was significantly shortened,” Mayer said. By 2024, the IAEA estimated that time had dropped to weeks or days, although there was no clear evidence that Iran had decided to build a nuclear bomb.
Efforts to revive or replace the nuclear deal continued for years, culminating in renewed negotiations in 2025 and 2026. The talks failed when the US, together with Israel, launched attacks on Iran on February 28, prompting Iranian retaliatory attacks on Israel and US allies in the Gulf.
After 40 days of fighting, the US and Iran agreed to a ceasefire on April 8. It is against this backdrop that talks between the two sides are now set to resume in Islamabad.
What’s on the table now?
At present the main controversy is about time. The US is demanding a suspension of Iran’s nuclear activities for 20 years, while Iran has said it is willing to accept sanctions for only five years.
Other major questions remain unresolved. Who will monitor Iran’s nuclear facilities? What will happen to its enriched uranium reserves? And how many centrifuges will Iran be allowed to have?
“The issues that need to be resolved now are, not surprisingly, the same issues that were addressed in the 2015 agreement,” the mayor said. “That agreement was about 150 pages with detailed contracts.” That’s why the mayor doubts a solution can be found within a few days or even weeks.
Why is the conversation difficult this time?
Many experts believe that the JCPOA was possible because a basic level of trust still existed between the parties. Today that base has largely disappeared.
Alan Eyre, who was part of the US negotiating team in 2015 and is now at the Middle East Institute, said both sides have hardened their positions. “There is tremendous mistrust and suspicion toward Iran on the American side, and toward the United States on the Iranian side,” he told DW.
Ayer also said that Iran had regained a strategic advantage. Despite suffering heavy losses in the war, Tehran still has the ability to retaliate with missiles, rockets and drones. It could also jeopardize shipping through the Strait of Hormuz and rely on regional proxy forces like Hezbollah or the Houthis – something it did not have in 2015.
Eyre said the current US administration lacks expertise when it comes to diplomacy, which takes time and sustained effort.
He said, “They’re really not used to doing that. They’re used to telling countries what to do and what countries are doing. So, it’s an open question whether J.D. Vance will be able to successfully negotiate with the Iranians, who are experienced and skilled negotiators.”
Experience and confidence matter as much as leverage, former negotiators say.
So, can Trump still get a better deal than Obama?
In one sense, experts say the answer may be yes. “It would be easier to get a better deal in the sense that many nuclear facilities have been destroyed,” Meyer said. “Iran may be more willing to accept that some of these sites are no longer on the negotiating table.”
However, politically the situation is much more complex than it was a decade ago. “We’re in a much worse situation than we were in 2015,” the mayor said. “The attacks have not solved the problem. They have made it worse, because more people in Iran now believe that nuclear weapons are needed to deter future American attacks.”
This has made it difficult to achieve long-term limits. As Washington and Tehran consider another attempt at diplomacy, the question is now not just whether a better deal is possible – but also whether the conditions that made the 2015 agreement successful can be recreated.
Edited by: Don McCoitir