As United States moves closer to a possible agreement with Tehran aimed at ending months of conflict, questions are resurfacing about the landmark 2015 nuclear accord that once shaped relations between Iran and the West.
The United States says negotiations with Iran are progressing, although the details of any new agreement have yet to be disclosed. That has prompted comparisons with the 2015 nuclear deal, formally known as the Joint Comprehensive Plan of Action (JCPOA), which was abandoned by President Donald Trump during his first term in office.
The agreement, reached between Iran and six world powers the United States, Russia, China, France, Britain and Germany were designed to curb Tehran’s nuclear activities in exchange for relief from international sanctions.
At the heart of the deal was a plan to significantly extend the time Iran would need to produce enough material for a nuclear weapon. Before the agreement, experts estimated that timeline at just a few months.
The deal sought to stretch it to roughly one year. Iran has consistently maintained that its nuclear programme is intended for peaceful purposes.
Trump withdrew the United States from the agreement in 2018, describing it as inadequate.
Washington subsequently reinstated sanctions on Iran, while Tehran gradually stepped away from many of the restrictions it had accepted under the accord. By 2025, United Nations sanctions had also been restored, effectively ending the deal.
Sanctions Relief
One of the biggest incentives for Iran was the lifting of economic sanctions that had crippled key sectors of its economy.
The United States, European Union and United Nations removed restrictions affecting Iran’s oil, gas, petrochemical, banking, shipping and automotive industries. Sanctions on trade involving precious metals and minerals were also eased.
In addition, Iran’s central bank and numerous companies and individuals were removed from sanctions lists. Washington also allowed limited commercial transactions, including the sale of passenger aircraft and imports of Iranian carpets and food products.
Limits on Uranium Enrichment
Under the agreement, Iran accepted strict limits on its nuclear activities.
The country agreed to cap uranium enrichment at 3.67 percent purity for 15 years far below the 90 percent level generally associated with weapons-grade material.
Iran had previously enriched uranium to levels as high as 20 percent.
Tehran also agreed to slash its stockpile of enriched uranium to 300 kilograms and significantly reduce the number of operating centrifuges, the machines used to enrich uranium. The number of centrifuges was cut from roughly 19,000 to about 6,100.
Excess enriched material was either diluted or shipped abroad, reducing Iran’s stockpile by approximately 98 percent, according to U.S. estimates.
The underground Fordow nuclear facility, once a major enrichment site, was converted into a research centre under the terms of the agreement.
Restrictions on Plutonium Production
The deal also addressed concerns over plutonium, another material that can be used in nuclear weapons.
Iran agreed to redesign its heavy-water reactor at Arak so it could no longer produce weapons-grade plutonium.
International Inspections
A key feature of the agreement was an extensive monitoring regime overseen by the International Atomic Energy Agency (IAEA).
Inspectors were granted broad access to Iran’s nuclear facilities and were tasked with verifying that Tehran was complying with the terms of the deal.
As diplomats work toward a possible new agreement, it remains unclear whether any future arrangement will mirror the framework of the 2015 accord or chart a different course. What is clear, however, is that the JCPOA remains the benchmark against which any new U.S.-Iran deal will be measured.
