Send In the Swarm

This quick take is part of our Crisis Crossroads series, which highlights timely analysis by CSIS scholars on the evolving situation in Ukraine and its security, economic, energy, and humanitarian effects.

The recent announcement that United States will send switchblade drones to Ukraine reflects the changing character of war and the importance of swarming. Swarming involves saturating a target with multiple small strikes as opposed to one decisive blow. By expanding arms transfers to include more capable swarming systems like the Israeli loitering munitions seen in Nagorno-Karabakh as well as new U.S. Marine capabilities like the Hero-120, the West can help Kyiv break the Russian sieges currently holding Ukrainian cities hostage.

Ukraine has already adapted tactical-level swarms to slow Russia’s advance. Similar to Finnish motti tactics, dispersed ambush teams attack Russian lines of communication to compound Moscow’s logistical challenges. In multiple instances, the Ukrainian armed forces have used drones to target artillery raids against Russian-seized airbases in Ukraine, including destroying as many as 30 vehicles and helicopters in Kherson.

Expanding the range and types of loitering munitions available to Ukraine will help them build on this success. The greatest threat to Ukraine right now is the ability of Russia to siege Ukrainian cities. The closer the Russian army gets to Kyiv, the more artillery and missile barrages it can fire on urban areas, putting pressure on Ukraine’s leaders to accept Russian demands. While surface-to-air missile transfers can help stop Russian aircraft and cruise missiles, they cannot stop artillery strikes. The same goes for anti-tank guided missiles, which perform the best ambushing convoys.

While the concept of swarming is as old as horse archers from ancient history, low-cost drones and persistent surveillance networks provide new technical means to the tactic. The result is an approach called mosaic that seeks to overwhelm adversaries short of a single, decisive battle.

Applied to the current war, long-range loitering munitions provide Ukrainian forces options for swarming Russian artillery and missile batteries striking cities like Kyiv and Mariupol. Faced with the prospect of suicide drones attacking their firing positions, already stretched Russian forces would have to pull back or reduce the volume of fire. The more Russian artillery and missile units Ukraine attacks, the harder it will become for Moscow to use medieval sieges as a negotiation tactic.

Swarming offers a low-cost, low-risk way of helping Ukraine defend its sovereign territory. Combined with sending surface-to-air missiles, it makes it more difficult for Russia to keep attacking Ukrainian cities in a way that limits escalation risks and helps accelerate a negotiated settlement.

Benjamin Jensen is a senior fellow for future war, gaming, and strategy in the International Security Program at the Center for Strategic and International Studies in Washington, D.C. 

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Benjamin Jensen
Senior Fellow, Futures Lab, International Security Program