The Biden administration’s decision to provide Ukraine with cluster munitions, a weapon widely banned for the inherent dangers they pose to non-combatants, is risky.
In addition to the immediate and long-term humanitarian consequences, the transfer of clusters jeopardizes the domestic and international political consensus around support for Ukraine which will be instrumental in ensuring military assistance can be sustained for the long haul.
Just a day before triumphantly announcing the final destruction of the remaining U.S. chemical weapons arsenal, the Biden administration revealed it was approving the export of another internationally banned weapon – cluster munitions to Ukraine.
The decision comes in spite of strong opposition from lawmakers, human rights defenders, and even U.S. allies involved in the military aid effort to Ukraine. The controversy reflects the globally recognized risk cluster munitions – projectiles that break apart and disperse dozens of smaller munitions – pose to civilians.
Though some have argued the provision of these intentionally condemned munitions may provide some battlefield advantage to Ukraine, they also pose serious humanitarian and strategic dangers that could jeopardize both civilian protection imperatives as well as the long-term sustainability of Ukraine’s international military aid enterprise.
Cluster munitions are a category of ordinance that breaks apart in mid-air, dispersing smaller sub-munitions over a large area, sometimes as wide as several football fields. Beyond the inherently imprecise nature of these weapons, many of the bomblets they scatter fail to detonate, leaving behind a large blanketing of unexploded ordnance that presents an enduring threat to civilians, especially curious children.
Accordingly, non-combatants make up the vast majority of those killed by cluster munition duds, with tens of thousands of civilian casualties since the 1960’s, including many that occur years after conflict has subsided.
More than 100 countries, including most of the United States’ closest allies, have signed on to an international convention banning their use or transfer and U.S. law prohibits the export of cluster munitions with a dud rate of over 1%, lower than even the most generous estimates of the ordnance being sent to Ukraine.
Additionally, the cluster munitions the United States is sending to Ukraine, known as Dual-Purpose Improved Cluster Munitions (DPICMS), are from old stockpiles with older fuses that have few safety features. DPICM duds are especially dangerous.
The legal and normative taboo, growing international consensus, and U.S. prohibitions surrounding cluster munitions place the Biden administration’s decision to proceed with their transfer to Kyiv in an especially harsh light.
Both Kyiv and Washington have argued that these weapons are essential for Ukraine’s efforts to dislodge occupying Russian forces, especially amidst a Ukrainian offensive that has been proceeding more slowly than its backers had hoped.
Some analysts have argued that these weapons provide a unique battlefield capability for Ukrainian forces, especially in terms of addressing Russia’s extensive networks of defensive trenches.
However, the U.S. government has explained that a major factor in their decision to provide cluster munitions rests on a broader effort to shore up dwindling Ukrainian and Western stockpiles of munitions, allowing the United States to draw from an alternative source without further depleting its own supplies of conventional artillery.
In other words, these munitions are meant to extend the time available to Ukraine to conduct its summer offensive by alleviating a supply crunch in shells made more acute by a slow-moving effort dependent on attrition of enemy defenses.
Despite these military-based rationales, the risks the provision of these weapons pose are both immediate and long-term, with consequences that extend beyond the summer offensive and beyond the war in Ukraine. In the first place, the inherently indiscriminate nature of cluster munitions adds to the civilian protection risks for Ukrainian civilians.
Indeed, cluster munitions used in Ukraine, overwhelmingly by Russian forces but also by Ukrainian troops, have already resulted in numerous civilian casualties. Moreover, the use of cluster munitions will increase the risks to Ukrainian troops by adding especially sensitive unexploded ordnance to already dangerous terrain they will have to traverse as they press forward with their offensive.
It is why, in addition to their humanitarian concerns, many veterans, including Retired Lt. General Mark Hartling, have voiced their own reservations about the transfer decision.
And while it has been suggested that these munitions will be used overwhelmingly in the open countryside and in areas already heavily mined by Russian forces, once these munitions are transferred it will be difficult for the United States to influence how they are employed.
Should fighting move to more densely populated areas, the temptation to continue to use all available weapons will be strong and could result in scenes reminiscent of Moscow’s widely condemned and ongoing use of cluster munitions in urban centers, especially during the early stages of the war.
The Biden administration insists it has assurances from Kyiv that these weapons will be used under strict conditions meant to limit civilian harm. But while Ukraine has taken great pains to limit civilian casualties, its fidelity to past commitments around the use of U.S.-origin weapons has been imperfect, adding to concerns around the efficacy of the risk mitigation measures the Biden team has put in place.
Secondly, using these cluster munitions will complicate and exacerbate what is already going to be a daunting demining enterprise.
Compared to their unitary munition counterparts, cluster munitions scatter far more dud weapons, not only adding to the volume of ordnance that will eventually need to be cleared but also to the challenge of finding them.
Cluster munitions have notoriously high dud rates, with even the most generous assessments placing the figure at between 2-14%. But even those numbers are thought to be undercounts, with significant variation in testing and real-world application, and without any meaningful transparency into how the U.S. government has conducted its assessments.
The administration says that it is transferring munitions with a dud rate of 2.5% – a figure that is both difficult to verify and in violation of U.S. law. Some analysis suggests that the failure rate of the weapons being transferred to Kyiv is far higher, with the potential to litter the region with hundreds of thousands of additional pieces of unexploded ordnance.
Additionally, a rapid expenditure of the supposedly lower dud rate munitions in Ukraine could lead the administration to start drawing down from even higher dud rate stocks, raising the risks of civilian harm and long-term humanitarian dilemmas.
Strategically, the transfer of these controversial weapons systems risks creating fissures in Kyiv’s alliance of international supporters which has been critical to Ukraine’s defense. Consensus among Ukraine’s backers has both enabled a more robust military assistance enterprise and denied from Moscow the opportunity to prey upon political divisions in the West to deter security assistance efforts.
Accordingly, electing to transfer weapons systems banned by most NATO members offers a compelling point of contention among governments aiding Kyiv’s defense, as well as polarizes even further domestic support for backing Ukraine. This is especially true in Europe, where public support for Ukraine remains sizable but divisive.
With no end to this conflict in sight, and with most analysts agreeing Ukraine will depend on international support for the long term, the provision of cluster munitions risks eroding the enduring political support necessary to sustain military assistance to Ukraine for the long haul.
Beyond Ukraine, the transfer of clusters sends a dangerous signal about the United States’ commitment to civilian protection and international norms. Whatever conditions the United States may say it is placing on its package to Ukraine, other governments across the world will feel their justifications for using, stockpiling, or selling cluster munitions are made far stronger.
Undermining the global taboo around these weapons risks making cluster munitions use more likely, including by governments with far less discerning human rights practices.
The Biden administration is well justified in providing Kyiv the means to defend itself against Russia’s illegal war of conquest. Moscow’s irredentism has wrought unimaginable damage to the country and people of Ukraine and shattered global norms around sovereignty, security, and civilian protection.
But beyond creating a lasting, life-threatening hazard for Ukrainian civilians, providing cluster munitions to Ukraine risks eroding the moral authority of the cause, and narrows the reputational gap that has both distinguished Kyiv’s defense from Moscow’s invasion and sustained its lifeline of international military support.
Arguments in favor of providing cluster munitions are narrow in scope and should not outweigh international law, norms, and the long-term interests of Ukraine’s people and its military aid enterprise.
Elias Yousif is a Research Analyst with the Stimson Center’s Conventional Defense Program. His research focuses on the global arms trade and arms control, issues related to remote warfare and use of force, and international security cooperation and child soldiers’ prevention.
Rachel Stohl is a Vice President of Research Programs at the Stimson Center and Director of the Conventional Defense Program. Prior to joining Stimson, Stohl was an Associate Fellow at Chatham House, the Royal Institute of International Affairs, from 2009-2011. She was a Senior Analyst at the Center for Defense Information in Washington, D.C. from 1998-2009.
