France, Britain, and Germany have formally initiated the process of triggering the “snapback mechanism” in response to Iran’s violations of the 2015 nuclear deal, also known as the Joint Comprehensive Plan of Action (JCPOA). This action sets the stage for the re-imposition of all United Nations sanctions on Iran, which had been lifted under the terms of the agreement.
What Happened
On September 19, 2025, France, Britain, and Germany—three key signatories to the 2015 nuclear deal—triggered the snapback mechanism, which will automatically reinstate sanctions that were previously suspended under the JCPOA. This decision comes after Iran’s consistent violations of the deal, which includes exceeding limits on uranium enrichment and continuing activities that the deal had specifically prohibited. The move escalates tensions between Iran and the European powers, as well as the United States, which had withdrawn from the agreement in 2018 under President Donald Trump.
Who Is Involved in This Decision?
The process has been led by France, Britain, and Germany, known as the E3, who have been instrumental in maintaining the nuclear agreement despite U.S. withdrawal. Iran, on the other hand, has repeatedly defied the terms of the 2015 agreement, which initially aimed to curtail Iran’s nuclear program in exchange for sanctions relief. The snapback mechanism, a part of the deal, allows any participant in the agreement to trigger the automatic re-imposition of sanctions if Iran is found to be in non-compliance.
Simon Mabon, Professor of International Politics at Lancaster University, provides key insights into the implications of this development and what it means for both international diplomacy and Iran’s nuclear ambitions.
Background or Timeline
The Joint Comprehensive Plan of Action (JCPOA) was established in 2015 after years of negotiations to limit Iran’s nuclear capabilities in exchange for relief from economic sanctions. Under the deal, Iran agreed to limit its uranium enrichment, allow inspections by the International Atomic Energy Agency (IAEA), and halt certain nuclear activities. In return, sanctions imposed by the UN, the U.S., and the EU were lifted.
However, after the U.S. unilaterally withdrew from the deal in 2018 under President Trump, Iran began to slowly abandon the constraints of the agreement, citing the failure of European nations to uphold their end of the bargain. This led to a series of violations, including exceeding uranium enrichment limits and interfering with IAEA inspections.
On September 19, 2025, the E3 invoked the snapback mechanism, stating that Iran’s actions had crossed the line into consistent and willful violations of the deal. This triggers the reimposition of comprehensive UN sanctions, which had been a cornerstone of the maximum pressure strategy on Iran’s nuclear program.
Public or Social Media Reaction
The news of the snapback mechanism has sparked widespread discussion, particularly in Europe, the Middle East, and the United States. In Iran, the government has rejected the decision, calling it a political move and arguing that the E3 had failed to honor the agreement themselves. Meanwhile, supporters of the move argue that it is necessary to ensure that Iran adheres to its commitments and does not continue to escalate its nuclear activities.
The U.S., which had previously withdrawn from the agreement, has largely supported the snapback sanctions. However, the move has placed significant pressure on the remaining signatories of the JCPOA, particularly in maintaining their relationship with Iran while addressing concerns over the nuclear program.
Official Statement or What Happens Next
The United Nations Security Council is expected to review the re-imposition of sanctions on Iran, which will automatically take effect within 30 days unless the council votes to block it. Given the current dynamics in the UN, it is unlikely that the council will be able to halt the sanctions without strong opposition from major powers like Russia and China, who have expressed support for the nuclear deal.
Iran has already warned of consequences if the sanctions are reinstated, including further reduction in its compliance with the deal and increased tensions in the Middle East. Diplomatic channels are expected to remain open as the international community watches closely to see how the situation unfolds in the coming weeks.
This story may be updated with more information as it becomes available.
