This article investigates how Moscow’s approach towards the Iran nuclear deal, the Joint Comprehensive Plan of Action (JCPOA), changed due to Russia’s renewed invasion of Ukraine in February 2022. It argues that the invasion marked an important inflection point in Russian diplomacy on the nuclear accord. Throughout 2021, Russia had presented itself as an active proponent of a restored JCPOA – mediating between relevant parties, averting a breakdown in Iran’s relations with the International Atomic Energy Agency (IAEA) on several occasions, and even publicly reprimanding Iran over breaches or delays in returning to the negotiating table.
Its invasion of Ukraine led Russia to decrease its support for a restored deal, though Moscow continued to profess commitment to the JCPOA as a matter of public rhetoric. As Russia – sanctioned and isolated by the West – became more reliant on Iran for battlefield support, it showed less ability and willingness to criticize Iran, or to push for meaningful progress in the nuclear talks. Since October 2022, Tehran’s crackdown on peaceful domestic protests and Russia’s intensifying reliance on Iranian battlefield support have further consolidated the Russian-Iranian partnership, diminished Russia’s desire to compartmentalize nuclear diplomacy from its confrontation with the West, and lowered the prospects for a JCPOA revival in 2023.