With measures to pass new US military assistance to Ukraine still stuck in Congress, Ukrainian President Volodymyr Zelenskyy recently singled out backing the country’s air defenses as one of Kyiv’s most critical priorities. “The most significant thing is to unblock the sky,” Zelenskyy remarked during a press event in Kyiv to mark the second anniversary of Russia’s full-scale invasion on February 25.

Recent reports suggest that unless Congress can break the current deadlock, Ukraine will face potentially disastrous shortages of ammunition and air defenses within weeks. Meanwhile, Russia is reportedly supporting its growing stockpiles with deliveries of ballistic missiles from Iran.

Ukraine’s Western backers have provided effective air defense capabilities over the past two years since the beginning of Russia’s invasion. This proved particularly important during the first winter of the war when Russia established a sustained air offensive against Ukraine’s civilian energy infrastructure in an alleged bid to freeze the country into submission and influence Kyiv to surrender.

Despite advancements in Ukraine’s air defenses, the country remains highly weak to Russian missile and drone attacks. While Kyiv now has fairly strong air defense coverage, other major cities such as Kharkiv, Odesa, and Zaporizhzhia are far less secure and regularly experience deadly bombardments.

The most precious assets within Ukraine’s patchwork air defenses are the Patriot systems the country has obtained from international partners. The US military’s most developed air defense system, Patriot batteries are capable of shooting down almost all of the missile types currently being employed by Russia to strike targets across Ukraine. The Ukrainian military has also reportedly deployed Patriots in an imaginative offensive capacity to shoot down Russian warplanes close to the front lines of the conflict.

So far, Ukraine has only acquired a handful of Patriot systems. Given their significance, Kyiv is understandably keen for more. Speaking in late February, Zelenskyy expressed the delivery of ten Patriot systems would be sufficient to have a significant effect on the course of the war. He claimed that this would allow Ukraine to protect big cities and vital infrastructure while also protecting the skies above the battlefield and potentially helping Ukrainian troops break through fortified Russian defensive lines.

At the same time, there is mention in Kyiv and among the country’s supporters that Ukraine’s air defense challenges cannot be decrypted by more Patriot systems alone. With individual missiles costing millions of dollars, the Patriot system is not a cost-effective option, particularly when targets include waves of relatively inexpensive kamikaze drones that Russia is acquiring from Iran and also producing domestically in increasingly enormous quantities.

Russia’s most destructive missiles, such as the Kinzhal, are often deployed within more extensive bombardments that include a degree of ballistic and cruise missiles alongside drones. These complicated attacks are particularly difficult for Ukrainian air defense units. “The most difficult is an attack by various types of aerial targets,” proved one Kyiv air defense commander in the summer of 2023.