Recent drone attacks on Russian facilities by Ukraine have signaled a crucial shift in momentum for Russia's war on Ukraine. The strategic use of drones has become a crucial part of Kyiv's strategy on the battlefield. Though Russia continues to use drones and missiles to launch attacks against Ukraine's cities, their effectiveness is declining, and the chances that Moscow can overwhelm Ukrainian air defenses are looking more and more slim.

Ukrainian forces have completed their training on more and better U.S. and European-made air defense systems that were pledged months ago. With winter now officially over and millions spent unsuccessfully trying to freeze Ukrainian civilians into submission, it is an open question whether the Russian military will keep targeting Ukraine's cities with the same vigor.

Ukraine dramatically increased its use of drones for strategic targeting this year as part of their effort to build an "army of drones." Ukrainian officials plan to spend over half a billion dollars on drones alone in 2023 to attack Russian soldiers at the front, and their military and oil facilities at the rear.

This growing drone capability of Ukraine makes things hard for Russian forces in two major ways. Firstly, Ukraine's drone fleet allows Kyiv to threaten supply depots, airfields, and other military sites that were once considered safe. Secondly, a robust Ukrainian "army of drones" puts Russia in the same air defense dilemma as Ukraine has been in since last October.

Protecting so much airspace with limited air defense systems will be costly for Russia, especially when they are needed at the frontline to deter Ukraine's other aircraft. Just as some experts were concerned about the U.S. sending expensive air defense for Ukraine to use against inexpensive drones, Russia will also have to choose between longer-range systems that are expensive or cheaper shorter-range systems that cannot defend wider areas.

Putin will need to think carefully about how to manage this new threat from Kyiv and whether his strategy of trying to use drones to "exhaust" the Ukrainian population is still within reach. Russia's smaller and less technologically advanced neighbor has gone from being a modest military power, which Putin assumed he could overwhelm in a week, to a formidable force. Now that Kyiv is poised to regain more territories, all while hitting major Russian cities with new innovations, Moscow's forces are left wondering where Zelensky's drones will strike next.