Russia-Iran Military Cooperation Strains US Weapons Stocks and Global Security

Russia and Iran are increasingly linking the Russia-Ukraine war with the US-Israel-Iran conflict, turning two wars that began in different regions, for different reasons and at different times into interconnected parts of a wider geopolitical struggle. As both conflicts drag on, their effects are spreading across a vast geographical area, from northern Russia to the Caspian Sea and from the Persian Gulf to the Gulf of Oman. These developments have made it increasingly difficult to view the wars as isolated regional conflicts.
Although Russia and Iran have not officially declared a joint war against the United States, their mutual cooperation is playing a growing role in the fighting. Before Israel and the United States launched joint attacks on Iran in February 2026, Tehran had been supplying Moscow with large quantities of inexpensive but lethal drones. When the war with the United States began, Iran became unable to continue those supplies at the same level because of its own military requirements. Russia subsequently began supplying Iran with lethal Gran drones.
Drawing on its extensive experience of confronting air defence systems deployed by the United States and Western countries in Ukraine, Russia had made these drones more advanced so they could penetrate Western defensive systems. The impact of these capabilities has become increasingly apparent over the past several months of the Iran-US war.
American and Israeli air defence systems have been unable to neutralise Iranian drone attacks consistently, contributing to a conflict that shows no immediate signs of ending. Cooperation between Moscow and Tehran, however, extends beyond the battlefield.
According to assessments by Western intelligence agencies, at least 14 Russian satellites operating in space are continuously sharing real-time geospatial, radar and signals intelligence with Iran. This intelligence support has helped Iranian forces repeatedly target American military installations in Gulf countries, inflicting considerable damage on US forces.
Russia's support for Iran is also intended to retaliate against attacks on its strategically important facilities that Moscow believes were carried out by Ukraine with the backing of the United States and Western countries. Another objective is to deplete American weapons stocks to the point where Washington cannot provide Ukraine with the same level of military assistance.
The consequences are becoming increasingly visible. The simultaneous Russia-Ukraine war and US-Iran conflict have placed considerable pressure on American military inventories. The Pentagon has warned that if another major global war breaks out at this stage, the United States could face the risk of exhausting its weapons stocks entirely.
To counter drone and ballistic missile attacks by Iran and groups supported by Tehran, the US military has been forced to deploy some of its most advanced interceptors. As a result, the United States has used approximately 80 per cent of its anti-ballistic missile system stockpile. Between 50 per cent and 60 per cent of its inventory of advanced Patriot missile interceptors has also been depleted.
The situation facing the United States in West Asia increasingly resembles the challenge it has created for Russia in Ukraine. At the heart of the crisis is the economics of low-cost, modern hybrid warfare. Russia and Iran are producing thousands of suicide drones and ballistic missiles every month at relatively low costs. In contrast, systems such as the American Patriot require complex technology and advanced guidance systems, making them considerably more difficult and expensive to manufacture.
American defence companies have been unable to produce these missiles quickly enough to match the rate at which they are being consumed on the battlefield. Ukrainian President Volodymyr Zelensky has said that, because missiles are being diverted to West Asia, Ukraine is now receiving only one-third of the air defence missiles it previously received.
The effects are also extending to the confrontation with China. The United States has warned its allies that weapons deliveries could be delayed by as much as five years. Deliveries of Tomahawk missiles to Japan have already been delayed by two years, while a $14 billion weapons shipment intended for Taiwan had to be halted midway to preserve American military stocks.
Meanwhile, Iran has already demonstrated its ability to exert pressure by closing the Strait of Hormuz. Through its Houthi allies in Yemen, it has now tightened its grip on two of the world's most important maritime energy routes by securing control over Bab al-Mandeb.
Saudi Crown Prince Mohammed bin Salman had appealed to the United States to launch attacks against the Houthis. However, the Trump administration refused to open another front in Yemen, citing the ongoing war with Iran, the active conflict in Ukraine and shortages of weapons.
Washington no longer has sufficient advanced weapons and defence systems to fight Iran, support Ukraine and simultaneously manage a new military front in Yemen, according to the assessment presented in the conflict's wider strategic context.
Russia, although not directly involved in the upheaval in Yemen, stands to gain substantially from the resulting disruption. As the Red Sea route becomes increasingly unsafe, crude oil prices have climbed above $106 per barrel. Higher prices have increased the value of Russian oil exports, providing an economic advantage to Moscow as it continues to face sanctions. Western countries, meanwhile, are bearing direct economic costs as fuel prices rise.
Together, these developments are exposing the limits of American military capacity while placing growing pressure on international security and economic stability. The interconnected wars are also challenging the global order that emerged after the First and Second World Wars and the dissolution of the Soviet Union, raising questions about the durability of the geopolitical arrangements that have shaped the modern world.