A three-way dance is developing between Washington, Moscow and Tehran over Iran’s nuclear program. Recently, U.S. President Donald Trump sent a letter directly to Iran’s supreme leader, Ali Khamenei, asking to enter negotiations, while indicating to the media separately that the alternative would be military action to prevent Iran from acquiring nuclear weapons. Khamenei responded by saying Tehran would not be bullied into diplomacy that simply translated into more restrictions on Iran’s foreign and security policies. Behind the scenes, however, Moscow has already increased its role in Iran’s nuclear program and could play a key part in negotiations with Washington as the two pursue a separate agreement on the war in Ukraine. In early March, the Kremlin revealed that Iran’s nuclear program was among the topics examined in high-level U.S.-Russia discussions in Riyadh the previous month, and that Moscow reportedly agreed to assist the administration in communicating with Tehran.
Earlier this year, Iran and Russia signed a Comprehensive Strategic Partnership Agreement, cementing their deepening collaboration across multiple sectors, including nuclear technology. Officially framed as a civilian energy initiative, the agreement has raised significant concerns over potential dual-use applications. Given Iran’s longstanding nuclear ambitions and intelligence reports suggesting growing Russian support, the deal has profound implications for regional security. The key question remains: Is Russia’s cooperation strictly for civilian purposes, or is it providing Iran with the means to advance toward nuclear threshold status?
Iran’s Nuclear Calculations: Deterrence or Energy Security?
Iran’s “forward defense” doctrine, long reliant on proxy networks and asymmetric warfare, has suffered significant setbacks in the past year. Systematic Israeli strikes have eliminated key officers in the Iranian Revolutionary Guard Corps (IRGC) and proxy leaders, such as Hezbollah’s Hassan Nasrallah and Hamas’s Yahya Sinwar, severely degrading Tehran’s ability to project power in the region. The December 2024 collapse of the Assad regime in Syria severed Iran’s main logistical route to Lebanon, while Israeli airstrikes further damaged key missile motor plants in Iranian cities Shahroud and Khojir, as well as a facility associated with nuclear warhead-component testing. These setbacks have led to internal debates within Iran on whether to rebuild its conventional forces or shift towards a nuclear-based deterrence.
As noted by Mohammed Alsulami, president of the International Institute for Iranian Studies, Tehran’s nuclear ambitions must be understood within the context of its strategic vulnerabilities: “Iran’s pursuit of nuclear deterrence is both a geopolitical bargaining chip and a burgeoning security threat. A revisionist power won’t invest so heavily without seeking eventual nuclear capability.”
As a threshold nuclear state, Iran has most of the essential components for nuclear weapons—although the latest U.S. intelligence assessments indicate that Iran is not actively building a nuclear weapon. Tehran’s ability to enrich uranium to near-weapons-grade levels has raised alarms within the international community. According to the February 2025 International Atomic Energy Agency (IAEA)’s quarterly report, Iran’s stockpile of 60% enriched uranium neared 275kg as of October 25—enough for developing several nuclear devices if further enriched to 90%, according to the International Institute for Strategic Studies (IISS). Iranian officials, including former Foreign Minister Kamal Kharrazi, have warned that Tehran may reconsider its nuclear doctrine in response to escalating threats.
While much of this discourse remains rhetorical, driven by figures lacking direct control over nuclear policy, it reflects hardliner efforts to leverage Iran’s threshold status as a deterrent. This ambiguity reflects Iran’s calculated strategy: maintaining nuclear threshold status to instill caution in adversaries while leaving room for diplomatic maneuvering. Yet, as Tehran’s conventional deterrence erodes, the temptation to cross the nuclear threshold may grow stronger.
As recent U.S.-Russia discussions have indicated, Washington appears to recognize that Iran’s nuclear trajectory requires diplomatic attention beyond economic sanctions. While Moscow claims to support “peaceful, political, and diplomatic solutions” regarding Iran’s nuclear ambitions, Russia’s strategic incentives remain unclear. Tehran, in turn, has signaled an interest in leveraging Moscow’s evolving stance to secure additional technical cooperation while keeping diplomatic channels open.
Why Is Moscow Helping Iran?
Russia has played a central role in Iran’s nuclear sector for decades, constructing the Bushehr Nuclear Power Plant and supporting Iran’s civilian nuclear infrastructure. However, recent developments suggest that Moscow’s support may extend beyond purely civilian projects.
With Iran’s regional deterrence weakened and Russia facing increasing military constraints in Ukraine, the two nations have strengthened their strategic cooperation. Tehran has emerged as a critical arms supplier for Moscow, providing Shahed drones and short-range ballistic missiles to support Russian operations in Ukraine. In return, U.S. and U.K. intelligence reports from September 2024 suggest that Russia may have expanded its nuclear assistance to Iran, allegedly providing expertise in nuclear fuel fabrication and other sensitive technologies in exchange for military hardware.
This growing partnership has triggered concerns that Moscow may be shifting its historical opposition to an Iranian nuclear weapon. In the past, Russia opposed Iranian nuclear weaponization, fearing it could trigger a regional arms race. However, Moscow’s break with the West over Ukraine and its reliance on Iranian military support may have shifted its calculus. While Russia may not explicitly endorse a nuclear-armed Iran, it could tolerate—or tacitly enable—Tehran’s progress to maintain strategic leverage against their mutual Western adversaries.
Moscow and Tehran’s nuclear cooperation is also closely linked to their missile and space technology collaboration. Russia’s assistance in Iran’s space launch vehicle (SLV) program has provided Tehran with critical missile technology, including advanced liquid rocket engines that could be repurposed for intercontinental ballistic missiles (ICBMs). This crossover between space and missile development raises concerns about Russia indirectly assisting Iran’s long-range missile capabilities.
In the immediate term, Iran appears focused on securing Russian support for rebuilding its air defenses, which were severely degraded by Israeli airstrikes throughout 2024. However, its long-term objectives extend beyond defensive restoration. While Iran does not require Russian assistance for uranium enrichment itself, Moscow’s potential contributions to nuclear warhead development, metallurgy and weapons miniaturization remain a key concern for Western and regional powers. If Russia’s calculus has indeed shifted toward tacitly enabling Iran’s nuclear ambitions, this would mark a major inflection point in global non-proliferation efforts.
The Gulf’s Perspective: Security Implications for the Region
Gulf states have long viewed Iran’s nuclear ambitions with alarm, seeing them as both a security threat and a geopolitical bargaining tool. As Iran moves closer to nuclear threshold status, the United Arab Emirates and Saudi Arabia are likely to accelerate their own nuclear programs. Saudi Crown Prince Mohammed bin Salman has previously stated that Riyadh will seek nuclear capability if Iran develops a weapon. The UAE, which has operated a civilian nuclear program since 2020, may similarly reconsider its policy of non-enrichment.
Russia’s broader military cooperation and provision of advanced technology to Iran, including the alleged supply of fighter jets, air defense and naval defense systems, adds to concerns from the Gulf states over the balance of power in the region.
The broader question is whether Gulf states see Russia as a potential mediator in restraining Iran’s nuclear ambitions or as a partner complicit in Tehran’s nuclear advances. Indeed, their own diplomatic outreach to Moscow may be insufficient to curb this alliance, according to Alsulami. With Russia increasingly dependent on Iranian military exports for the war in Ukraine and now positioning itself as a potential diplomatic intermediary between Tehran and Washington, Gulf states might worry that Moscow’s incentives to curb Iran’s nuclear development have diminished.
If Iran continues expanding its nuclear program with Russian support, the regional security architecture will face profound shifts. Saudi Arabia and the UAE have already signaled interest in pursuing their own nuclear energy capabilities, and an unchecked Iranian program could accelerate nuclear proliferation across the Middle East. Türkiye and Egypt, two other regional heavyweights, may also feel compelled to follow suit.
As Tehran navigates its deteriorating conventional deterrence, its reliance on nuclear ambiguity as a strategic tool will likely increase. Whether Russia continues to walk a fine line or actively accelerates Iran’s nuclear trajectory remains an open question. Recent diplomatic developments thus indicate that Moscow is integrating Iran’s nuclear program into its broader strategic calculus—potentially using it as leverage in discussions with Washington. This suggests that while Russia may continue its nuclear cooperation with Tehran, evolving U.S.-Russia negotiations could shape its long-term approach.
While Iran has not yet made the definitive leap toward weaponization, the confluence of geopolitical factors—Iran’s regional setbacks, Russia’s shifting strategic interests, and Gulf states’ growing concerns—suggests that the nuclear question is far from settled. The coming months will be critical in determining whether Iran remains a threshold state or if Moscow’s cooperation pushes it closer to the nuclear brink. Either scenario carries profound implications for regional security and global non-proliferation efforts.
