Russia’s brutal full-scale invasion of Ukraine has killed thousands of people and displaced millions of civilians. Ukrainian cities have been leveled and villages have been turned into wastelands. U.S. and allied diplomatic, military, and intelligence support to Ukraine, including over $40 billion in security assistance since the war began, is essential to its defense and an eventual end to the conflict.

However, providing some types of lethal U.S. and European military assistance to Ukraine would be escalatory, counterproductive, and only further increase the dangers to civilians caught in combat zones and those who will, someday, return to their cities, towns, and farms.

As Ukraine’s latest counteroffensive continues, some members of Congress and Ukrainian officials are pressing the Biden administration to drop its opposition to providing Kyiv with a class of weapons – cluster munitions – that are prohibited by an international agreement and are not as effective on the battlefield as proponents for their use claim. The Biden administration is reportedly considering the proposal, though a final decision has not been made. Transferring these controversial weapons would be a mistake and could harm civilians now and for decades to come.

Cluster Munitions are Indiscriminate Weapons

Cluster munitions are designed to disperse or release explosive submunitions, each of which weigh less than 20 kilograms. The U.S. stockpile includes dual-purpose improved conventional munitions (DPICMs), surface to surface warheads, and other types of cluster munitions. Given that cluster munitions disperse hundreds or even thousands of tiny but deadly bomblets, their use produces significant quantities of unexploded submunitions that can maim, injure, or kill civilians and friendly forces during, and long after, a conflict.

The limited military value and the indiscriminate impacts of these weapons led to the majority of the world’s countries to negotiate the 2008 Convention on Cluster Munitions. The treaty – which over 120 nations have joined – prohibits State parties from developing, producing, acquiring, using, transferring, or stockpiling cluster munitions. While twenty-three NATO members are parties to the treaty, the United States, Ukraine, and Russia are not.

Providing U.S. cluster munitions to Ukraine would require a decision by President Biden, who has so far refused to send the controversial weapons and would further require his administration to use a waiver in the law that usually restricts the transfer of cluster munitions that result in more than a one percent rate of unexploded ordnance. This restriction was established because the U.S. has assessed that the “failure” rate of most cluster munition stockpiles exceeds one percent, which results in an unacceptably high percentage of persistent post-combat submunitions.

Still, some members of Congress and some U.S. officials claim that these weapons “would be useful” against mass formations of troops and armor or broad targets, such as airfields, and that they would allow Ukraine to concentrate their use of unitary warheads against higher-value Russian targets.

Providing Cluster Munitions to Ukraine is Counterproductive

The reality is more complicated. What’s clear is that cluster munitions are not the “winning weapon” in Ukraine’s fight for its future, and the country’s ongoing counteroffensive does not hinge on the delivery of any one particular weapon.

The effectiveness of cluster munitions is significantly oversold. Kyiv has already allegedly used cluster munitions in Eastern Ukraine in 2022, and the use of the weapon did not deliver results that could not have been produced by alternative munitions, and their use of these weapons put civilians in Ukraine at much greater risk. When Russia was reported to have used cluster munitions in Ukraine in 2022, the U.S. Ambassador to the United Nations, Linda Thomas-Greenfield, condemned the move saying that cluster munitions are “banned under the Geneva Convention” and have “no place on the battlefield.”

Cluster munitions cannot differentiate between a Russian soldier and a Ukrainian soldier. They would put advancing forces (and civilians) at risk of encountering unexploded ordnance from earlier bombardments. U.S. forces experiencedserious fratricide dangers when it employed cluster munitions in Iraq the 1990s.

The limited military utility and the substantial humanitarian dangers of these weapons are among the key reasons why the Defense Department halted using them in Afghanistan in 2002 and Iraq in 2003, and has chosen to invest in alternative munitions. It is why, in 2008, former Secretary of Defense Robert Gates issued an order to phase out by 2018 cluster munitions with an unexploded ordnance rate of greater than one percent, and it is why, in 2011, the Obama administration affirmed this policy. It is why Congress, in 2018, enacted a series of export restrictions on cluster munitions with a failure rate in excess of one percent.

Unfortunately, in 2017, Deputy Secretary of Defense Patrick Shanahan announced that the military would not meet the 2018 deadline for phasing out non-compliant clusters munitions and did not set a new deadline. Instead, the Trump administration’s policy allows the U.S. to use the cluster munitions in existing stockpiles “until sufficient quantities” of “enhanced and more reliable” versions are developed and fielded. How large the outdated U.S. cluster munition stockpile, and what the notional failure rate may be, are not clear. One U.S. official, however, reportedly claimed that the two types of munitions under discussion for transfer to Ukraine have dud rates of approximately 1.3 percent and 2.5 percent, which would create significantly higher amounts of unexploded bomblets. The official dud rates of the updated versions of the cluster munitions in the U.S. stockpile are classified.

If the United States were to equip Ukrainian forces with some of its older cluster munitions, it would require training and time. Any attempts to rush these weapons onto the battlefield could increase the dud rate, thus, increasing the likelihood of harm to Ukrainian forces due to friendly fire.

Furthermore, a decision by the United States to transfer cluster munitions to Ukraine would create serious alliance management problems within NATO. Currently, more than two-thirds of all NATO members, including the United Kingdom, France, Germany, and Spain, do not support transferring cluster munitions to Ukraine due to the humanitarian risks posed by these weapons. Transferring cluster munitions to Ukraine would potentially fragment the Ukraine Defense contact group and fracture NATO’s image of a united front willing to support Ukraine “as long as it takes.”

If Biden were to reverse his opposition to sending prohibited cluster munitions to Ukraine, it would also cede that moral high ground that has been crucial for sustaining support for Ukraine’s effort to defense itself. Moscow, which has already used cluster munitions in the war would cynically frame a decision by Washington to supply these weapons to Kyiv to sow doubt about Ukraine’s cause among non-aligned countries.

Currently, Washington is providing Ukraine with other munitions that are important for its military effort to repel Russia’s forces, including regular 155-millimeter munitions and a new type of 155-mm millimeter artillery shell that can hit targets with greater precision.

Instead of debating over controversial requests for banned cluster munitions, Washington and its allies could focus more energy on creative ways to provide Ukraine with the precision-guided munitions. For instance, the Biden administration struck an agreement in late May with South Korea to transfer hundreds of thousands of artillery rounds to Ukraine.

Throughout the course of this horrific conflict, Ukrainian forces have consistently surpassed battlefield expectations without resorting to the widespread use of controversial weapons, including cluster munitions.

As Biden noted on the one-year anniversary of Russia’s brutal and unprovoked invasion, “the decisions we make over the next five years are going to determine and shape our lives for decades to come… a choice between chaos and stability.”

The United States needs to make clear that it supports stability, not chaos, and do so by making it clear that cluster munitions need not and should not be part of the conflict in Ukraine, or in any war.

IMAGE: The remains of artillery shells and missiles including cluster munitions are stored on Dec. 18, 2022 in Toretsk, Ukraine. (Photo by Pierre Crom via Getty Images)