Western intelligence assessments indicate that Iran’s ballistic missile arsenal has been cut in half - from roughly 2,500 projectiles down to approximately 1,200, with only 100 serviceable launchers still operational. For a regime that spent decades building its missile program as the cornerstone of regional deterrence, the depletion represents an existential crisis and much of it’s effectiveness now comes down to math.
What makes Tehran’s predicament acute is the abandonment by traditional backers. Russia has ceased arms shipments while providing intelligence to help Iran target U.S. forces, according to multiple U.S. officials. China, facing confrontation with Washington over Taiwan, has quietly distanced itself from Iranian crude purchases. The result is an Islamic Republic that is more isolated than at any point since the 1980s, with its conventional deterrent crumbling and options narrowing to a single dangerous path.
Arsenal Depletion and Russia’s Intelligence Lifeline
Dr. Andreas Krieg, associate professor at King’s College London, tells The Cipher Brief that while the drop from roughly 2,500 ballistic missiles to closer to 1,200 is significant, “this is not a ‘disarmed Iran’ story.”
Iran still has weapons, but can no longer sustain weeks of intensive missile attacks, forcing it to rely more heavily on cheaper drones and carefully ration its remaining high-end missiles for maximum political impact.
What Iran lacks in replenishment, Russia has partially offset through intelligence. U.S. officials say Russia has been providing Iran with targeting information since the war began, including the locations of U.S. warships and aircraft. The assistance reportedly also includes imagery gathered by Moscow’s sophisticated satellite constellation.
Subsequently, Iran has been making precise hits on early warning radars and command infrastructure, patterns consistent with intelligence-sharing. Iranian drones struck a CIA station at the U.S. Embassy in Riyadh and killed six U.S. service members at a facility in Kuwait.
Rosemary Kelanic, director of the Middle East Program at Defense Priorities, tells The Cipher Brief that Russia and China can still help Iran beyond arms shipments.
“Either might help Iran with targeting by clandestinely providing satellite and other intelligence. Some evidence suggests that Russia helped the Houthis with targeting Red Sea shipping in recent years,” she notes.
The Drone Factor: Mass Production Versus Interceptor Economics
Beyond missiles, Iran’s real staying power lies in its vast drone arsenal. Israeli intelligence officials estimate Iran maintains more than 10,000 Shahed drones in storage. Robert Tollast of the Royal United Services Institute puts the figure even higher at “tens of thousands.” Some estimates suggest Iran may possess as many as 80,000, though such figures remain difficult to verify.
The economics, however, favor Tehran. Each Shahed-136 costs between $20,000 and $50,000, while interceptors cost exponentially more. For every dollar Iran spends, the UAE, for one, pays approximately $20 to $28 to intercept. Moscow has reportedly established a factory capable of producing 310 drones per month.
If Tehran sustains output approaching 400 drones daily, a figure cited in recent intelligence estimates, then annual production would exceed 140,000 units. Such capacity requires distributed manufacturing across multiple sites, a model Iran developed during the Iran-Iraq War in order to reduce vulnerability.
But Iran’s ability to keep launching depends on suppression efforts. The question isn’t just stockpile size - it’s whether Iran can protect launch sites and coordinate mass attacks while under continuous bombardment.
The Interceptor Crisis
As a result of America’s own supply problem, Iran’s drone advantage is amplified. Last June, American THAAD interceptor stocks were depleted by 25 percent. Officials at the Pentagon privately acknowledge that replenishment timelines extend into 2027.
Miguel Miranda, founder of the Southeast Asian monitoring service, Arms Show Tracker, tells The Cipher Brief that while “CENTCOM can airlift fresh missile interceptors and even more Patriot batteries as needed, the problems are the emerging missile and air defense gaps in friendly countries and their own defenses.”
He also observes that while there seems to be real success by CENTCOM and Israel in destroying the heavier Khorramshahr and Ghadr-class MRBMs, Iran’s most powerful medium-range ballistic missiles capable of striking Israel and carrying multiple warheads, “the visuals for these are very limited.”
“One week into this mess, we do not have a clear picture of the Iranian missile arsenal,” Miranda told us.
Michael Rubin, senior fellow at the American Enterprise Institute, tells The Cipher Brief that Washington’s supply chain issue represents “strategic negligence going back decades.”
“After the missiles and drones are depleted, and it does not appear Iran is holding any in reserve, then not only are regional states safe, but the U.S. and Israel can begin close air support operations,” he observes.
Yet the interceptor shortage cuts both ways. Kelanic underscores that “limitations on interceptors likely play an outsized role in Iran’s overall strategy,” pointing out that while the U.S. and Israel can continue fighting without top-tier interceptors, they will suffer higher casualties.
“Iran’s leaders recognize that if the war evolves into an attrition conflict, a battle of wills more than a battle of capabilities, Iran could have the upper hand, because the stakes are existential for Iran but not for the United States,” she said.
It’s a war of ammunition math, not just technology. Krieg explains the THAAD drawdown matters “because missile defense is a magazine contest, not a pure technology contest.” Iranian planners, he predicts, will exploit this with “missile math: using low-cost drones and decoys to trigger high-value intercepts, and reserving ballistic missiles for moments that maximise political impact.”
The UAE, for one, reported that 65 of 941 Iranian drones detected fell within its territory, damaging ports, airports, hotels, and data centers.
Moscow’s Constraints and Beijing’s Calculation
While Russia provides intelligence, it cannot provide the weapons Tehran desperately needs. Russia’s relationship with Iran has long been a cornerstone of its Middle East strategy. Yet, the Kremlin, consumed by its protracted war in Ukraine, now finds itself unable to deliver military support. MI6 assessments indicate Russian arms exports have effectively halted, with production lines committed to Ukraine.
Russian President Vladimir Putin faces a paradox. Elevated oil prices above $100 per barrel, driven partly by Middle East instability, boost Russian revenues. But meaningful military intervention would require diverting resources from Ukraine or exposing force depletion to NATO intelligence. Russia’s posture has become rhetorical support without substantive backing. Arms shipments have dried up, replaced by intelligence sharing.
China’s calculus proves even more complex. Iranian crude accounts for 13 percent of China’s oil imports. Still, Beijing faces an uncomfortable reality. The Strait of Hormuz remains vulnerable, and continued procurement risks a crisis with Washington as Taiwan tensions reach their highest levels in decades.
As the Trump administration challenges Chinese ambitions in the Pacific, Beijing cannot afford to engage in multiple confrontations at once. As Chinese energy companies reduce their exposure to Iran, they are looking for alternatives in Russia and Gulf countries.
Krieg argues that “the lack of Russian resupply and China’s reluctance to jeopardize Gulf relationships increases Tehran’s sense that it cannot ‘outlast’ the West conventionally through replenishment.”
“This isolation makes the nuclear program more valuable as an insurance policy: not necessarily to sprint to a bomb immediately, but to sit closer to the threshold so that regime survival looks too costly to challenge,” he explains.
The Nuclear Trump Card
Faced with a depleted conventional arsenal, absent Russian resupply, and Chinese abandonment, Tehran has increasingly concentrated resources on its nuclear program. Western intelligence agencies monitoring Iranian facilities report accelerated enrichment activities and renewed weaponization research.
The Iranian government has grown increasingly explicit in its nuclear messages, suggesting that its nuclear program represents an existential guarantee of the regime’s survival. Despite this, expert assessments of Iran’s nuclear trajectory differ sharply.
Rubin points out that the late Supreme Leader Ali Khamenei “could never compromise on Iran’s nuclear program because he could not forfeit it and explain to his base that their sacrifice, as Iran lost $2 trillion in lost revenue due to sanctions and lost opportunities, was worth it.” He also warns that while Tehran’s bluster is primarily about leverage, “Iran might not be able to explode a fissile device, but it can make a dirty bomb.”
Kelanic, meanwhile, notes that Israeli intelligence has so deeply penetrated Iran’s security services that the regime has little chance of weaponizing without detection.
“Iran’s only nuclear leverage is the knowledge of where its HEU stockpiles are, coupled with the implicit threat that nuclear materials could fall into worse hands than the current regime if the country splinters into chaos,” she asserts.
HEU, highly enriched uranium, is weapons-grade nuclear material. Essentially, Iran’s bargaining chip is the threat that if the regime collapses, its nuclear stockpiles could end up with even more dangerous actors, like terrorist groups or warlords.
Yet Krieg sees Iran’s acceleration primarily as leverage and survival hedging.
“The pattern fits a long-standing approach. Move closer to the threshold, protect stockpiles and facilities, compress breakout timelines, and keep ambiguity high so that opponents face deterrence without Tehran crossing a line that would trigger overwhelming retaliation,” he says. “In an existential war, the probability of a last-resort dash is higher than in normal times, especially if leaders conclude the conventional balance cannot preserve the regime.”
Yet Kelanic emphasizes that Tehran retains options beyond ballistic missiles.
“Iran can mass-produce drones, which so far have caused significant damage. Iran can also harass oil shipping in the Persian Gulf with limpet mines attached by speedboats,” she cautions. “There are many low-tech, low-cost ways Iran can retaliate in the region.”
Cut off from Russian weapons and Chinese support, Iran’s nuclear program has become its most valuable bargaining chip, both to deter attacks and to potentially trade for the sanctions relief it desperately needs to rebuild its conventional forces.
How Long Can This Last?
President Trump stated the war was initially projected to last 4 to 5 weeks, adding that the U.S. has “the capability to go far longer.” But that timeline could depend on factors neither side controls. Iran must protect manufacturing sites under bombardment while American forces maintain tempo with finite interceptor stocks and mounting domestic pressure.
Tom Sharpe, a former Royal Navy commander, warned that “if the Iranians unleash everything - go hard and fast if the regime feels threatened, then eventually the U.S. will run out of THAAD and Patriot interceptors.” Yet Iran cannot expend missiles recklessly; once depleted, the regime becomes defenseless.
History offers sobering precedents. The Soviet invasion of Afghanistan began as a six-month intervention; it became a nine-year quagmire that accelerated the USSR’s collapse. It becomes a question of whether Tehran calculates that it can survive by hoarding resources and hoping America breaks first, or if it is driven by existential desperation.
“The most realistic interpretation,” Krieg concludes, “is that Iran is using the nuclear program to regain bargaining power now, while keeping weaponization as an option of last resort if it believes the state is facing collapse.”
Are you Subscribed to The Cipher Brief on YouTube? There is no better place to get clear perspectives from deeply experienced national security experts.
Read more expert-driven national security insights, perspective and analysis in The Cipher Brief because National Security is Everyone’s Business.
