One year into the Russian invasion of Ukraine, Moscow’s relations with Tehran have entered a new phase, marked primarily by closer diplomatic and military cooperation—and also agreements to boost economic ties. 

Most international attention garnered by the expanding bilateral relationship has been centered on Russia’s reported use of Iranian drones in Ukraine. On a broader level, there has also been a focus on the growing anti-western component of cooperation between the two countries. That said, one critical area of bilateral collaboration has been relatively overlooked: Syria, where Iran and Russia have worked hand in hand over the last decade to support the regime of President Bashar Al-Assad. 

In the early weeks of the invasion of Ukraine, there were speculations that Russia’s need to focus on the operation as well as restricted diplomatic and military bandwidth would highlight the element of competition with Iran in Syria. The argument was that this would provide Tehran with an opportunity to gain the upper hand. However, there are indications that—as in the...