Cluster Munitions and Rearming for Great Power Competition


If you are among those who believe that the U.S. military needs to better equip and prepare itself for a new era of great power competition, Nov. 30, 2017 was a significant day: The Department of Defense changed its cluster munitions policy. The old policy, which had been in place since 2008, “established an unwaiverable requirement that cluster munitions used after 2018 must leave less than 1% of unexploded submunitions on the battlefield.”

The new policy holds that the department will retain existing stocks of cluster munitions until suitable replacements are fielded. In explaining the basis for this new policy, Defense Department spokesman Tom Crosson said:

Ultimately, it was clear to DoD’s senior leadership that removing use of current stocks would have created a critical capability gap for our forces, risking much greater military and civilian casualties in a conflict, and weakening our ability to deter potential adversaries.

Why did the policy change ten years ago in the first place?

The Convention on Cluster Munitions entered into force in August 2008 and has “120 members committed to the goals of the Convention.” Ratifying states “commit to never use, produce, stockpile or transfer cluster munitions” and drove a clarifying U.S. policy. The United States did not join the convention (nor did Russia, China, Israel, Egypt, India, and Pakistan), because, as then Acting Assistant Secretary for Political-Military Affairs Stephen Mull stated in May 2008, the United States relies on cluster munitions and prefers “to pursue technological fixes that will make sure that these weapons are no longer viable once the conflict is over.”

The convention defines a cluster munition as “a conventional munition that is designed to disperse or release explosive submunitions each weighing less than 20 kilograms, and includes those explosive submunitions.” They “are dropped from aircraft or fired from the ground or sea, opening up in mid-air to release tens or hundreds of submunitions, which can saturate an area up to the size of several football fields.” The principal objections to the use of cluster munitions are two-fold. First, they have area effects that do not distinguish between civilians and combatants. Second, a small percentage of submunitions (the explosive bomblets) may not explode when they are meant to, leaving behind hazardous ordnance for years.

Even though the United States did not join the convention, the Department of Defense restricted the use of cluster munitions that exceeded a 1 percent unexploded ordnance threshold. Secretary of Defense Robert Gates’s 2008 memorandum directed demilitarization of any stockpiles exceeding operational requirements and prohibited employment after 2018 of any systems unable to meet the 1 percent unexploded ordnance. Although recognizing the operational utility of cluster munitions, the policy was “intended to minimize the potential unintended harm to civilians and civilian infrastructure of U.S. cluster munitions employment to the extent possible.” Thus, the key policy changes in 2017 were the abandonment of the 2008 “unwaiverable requirement that cluster munitions used after 2018 must leave less than 1% of unexploded submunitions on the battlefield” and the end of the 2018 deadline to replace noncompliant munitions.

It was therefore not a surprise that the new policy was met with substantial backlash. Sen. Patrick Leahy’s statement in response is representative:

In these cases the Pentagon not only can’t be relied on to keep its commitment; it is perpetuating the use of an indiscriminate weapon that has been shown to have high failure rates, with devastating consequences for civilians.

Mary Wareham of Human Rights Watch insisted “there is no compelling reason for the use of cluster munitions.” And Daryl Kimball, executive director of the Arms Control Association, decried the policy shift:

Reversing current U.S. policy in a way that resumes the use of even more dangerous types of cluster munitions, which the past two administrations decided were unnecessary, would be self-defeating and harmful to U.S. interests and to civilians caught in the middle of war zones.

So why might the Department have thought this change was necessary? It is worth exploring the proposition that the recent shift in the type of adversaries that the U.S. military is likely to face merits a reassessment of the military need for different types of weapons systems. This would include not just cluster munitions, but anti-personnel landmines outside the Korean Peninsula, as well as a modernized and diversified U.S. nuclear arsenal.

The World Has Been Here Before

The United States, after a long post-Cold War period during which it had few military peer adversaries, might be beginning to address certain capabilities it needs to prevail against such actors now that they have resurged. Over the past 25 years, weapons that many believed would never be needed again were proscribed by treaties and agreements all supported by popular movements. These include the Oslo Convention to eliminate cluster munitions, the Ottawa Convention to ban anti-personnel landmines, and several movements and treaties to reduce, limit, or zero out nuclear weapons stockpiles and stop further proliferation. Historically, these types of conventions and movements are not unusual in the aftermath of wars — or even in their absence. They might also garner popular support because they promise to prevent the unimaginable from happening again.

In the 20th century, the number of blueprints for disarmament certainly proliferated and have often failed. The Hague Peace Conferences before World War I, several treaties in the 1920s and 1930s to limit naval armaments to preclude another naval arms race like that which preceded World War I, and the 1928 Kellogg-Briand Pact to outlaw war. The pact had 62 signatories, including Germany, Italy, and Japan, which all obviously abandoned the agreement not too long after they signed.

These treaties, and many others, enjoyed great support, particularly after two world wars, when nations sought a better world by ending ruinous arms races and abolishing heinous weapons. They also offered a sense of collective security because, at their core, they assumed that compliance by all parties was unequivocal, given the inherent righteousness of the agreements their supposed transparency and, in some cases, verification regimes. Furthermore, absent a clear threat, these agreements also supported a peace dividend, like they did after the Cold War, that could be spent on domestic priorities.

The naval limitation efforts are a good case study to glean insights from how these well intentioned efforts can fail and, indeed, put compliant countries at a disadvantage to violating states. Before World War II, naval limitations enjoyed strong political and popular support in the United States and Great Britain. This continued even as a militarizing Japan was building a navy that violated the treaties it had signed. Verifying treaty compliance in the open, democratic United States and Great Britain was a simple matter, but much more difficult within a closed Japan. Thus, as Robert Gordon Kaufman notes in Arms Control During the Pre-Nuclear Era: “Naval limitation became folly only when the United States and Great Britain persisted in their efforts even after world conditions had changed manifestly for the worse.” Ironically, “America’s unilateral restraint in naval building not only failed to induce Japan to reciprocate, but may have tempted the Imperial Navy to engage in an unrestrained naval race, which increased the risk of war.”

Now, history is again rhyming as the United States faces the prospect of renewed great power competition after thinking for decades only about what was necessary to confront second- and third-tier adversaries. Make no mistake about it: Russia and China are modernizing their militaries. For its part, Russia is surreptitiously skirting previous arms control treaties, including the 1987 Intermediate Nuclear Forces Treaty. Once again, world conditions have changed. Certainly, Russia and Syria are violating the Law of Armed Conflict in their purposeful bombing of Syrian civilians, while Syria has violated the Chemical Weapons Convention to which it is a signatory.

“Precision” and Disarming After the End of History

In the absence of a competent adversary that required cluster munitions, anti-personnel landmines, and land-based tactical nuclear weapons, the United States has largely employed weapons with precision, point effects optimized to create as little collateral damage as possible. This was a policy, rather than a legal requirement. The United States is a signatory to the Geneva Conventions of 1949 and many of its additional protocols that constitute the legal requirements for the Law of Armed Conflict. Defense Department policy is contained in the 2015 Department of Defense Law of War Manual as well as in service manuals. The United States and its military forces adhere to five foundational principles of the Law of Armed Conflict: distinguishing between participants in a conflict and civilians, military necessity, prohibiting unnecessary suffering, taking precautionary measures to mitigate risks to civilians, and proportionality or weighing the anticipated harm to civilians against the anticipated military value of the attack. Indeed, the United States has as a matter of routine applied more restrictive rules of engagement for the use of force than is required by the Law of Armed Conflict.

Again, this restraint was possible because the U.S. military was largely uncontested for the past 25 years, except in the land domain, and there mainly by irregular adversaries. Military requirements could be met with precision weapons and highly restrictive rules of engagement designed to avoid civilian casualties and collateral damage. Precision weapons met most military necessity requirements against what were largely point and high-value targets.

Furthermore, the United States rid itself of many of its Cold War capabilities (e.g. ground-based tactical nuclear weapons) or has chosen not to use them (e.g. cluster munitions and anti-personnel landmines). It has also, until recently, not invested significantly in research and development for these weapons — because they were not deemed necessary and there were other items that had priority in Iraq and Afghanistan, e.g., mine-resistant ambush protected vehicles, and the efforts to counter improvised explosive devices. This was possible because the United States military could operate effectively within these self-imposed restrictions due to the limited capabilities of the enemies it was fighting. This is no longer true. And, as Michael Jacobson and Robert Scales commented in these pages, cluster munitions and artillery systems to deliver them provide an important capability against peer adversaries.

Potential state adversaries — China, Russia, North Korea, and Iran — outlined in the 2018 National Defense Strategy merit a fresh look at U.S. policies and capabilities. Russia, since the Cold War, has willfully employed or supplied mines, cluster munitions, sensor-fused weapons, and thermobaric weapons in Chechnya, Georgia, Ukraine, and Syria and is modernizing its conventional and nuclear arsenals. However, any argument for the United States to employ cluster munitions, anti-personnel landmines, and modernize and extend its nuclear deterrent cannot be one of tit-for-tat. Rather, it would need to be one of military necessity.

Military Necessity

What constitutes military necessity has dramatically changed. China and Russia have created anti-access/area-denial (A2/AD) systems that significantly impede the freedom of action to which the United States has become accustomed. Even North Korea has massed artillery and ground formations positioned perilously close to South Korea (hence the U.S. policy allowing anti-personnel landmines in the defense of South Korea). The North Koreans also have theater nuclear weapons, and are on the cusp of having an intercontinental nuclear capability that can threaten the United States.

A simulated Russian attack against the Baltic states, examined in RAND Corporation tabletop wargames, is illustrative of the problems the U.S. military must be prepared for in the future. The problem has several components: neutralizing air defense systems, countering long-range fires, stopping mechanized ground maneuver, and deterring the use of nuclear weapons.

Russian A2/AD systems and their land targets are comprised of area targets, i.e., are spread out over large areas to make them more survivable. Precision, pinpoint attacks do not eliminate these systems. Thus, ironically, one of the principal reasons cited on the Convention on Cluster Munitions website for why cluster munitions are unacceptable is that they have wide area effects. This is precisely the reason the U.S. military needs cluster munitions, as pointed out in the 2017 Defense Department policy:

Cluster munitions provide the Joint Force with an effective and necessary capability to engage area targets, including massed formations of enemy forces, individual targets dispersed over a defined area, targets whose precise location are not known, and time-sensitive or moving targets.

Anti-personnel landmines may also be needed to address these challenges. Many artillery, air defense, and tank and mechanized infantry units rely on rapid displacement and high levels of mobility to survive, thus, requiring not only munitions with area effects, but mines to impede their movement.

This is why the United States fielded the family of scatterable mines to defend NATO member territory, including the Remote Antiarmor Mine, the Artillery-delivered Antipersonnel Mine, and GATOR aerial-delivered systems with anti-personnel landmines and antiarmor mines. The comments of Gen. Donn A. Starry, then U.S. Army Training and Doctrine Command show why they were deemed necessary. He saw them as a

relatively cheap combat multiplier that can enhance the effectiveness of the other parts of the team . . . tanks, infantry, fighting vehicles and the artillery. Targets are destroyed, disorganized, or better yet, disrupted.

Indeed, the Soviets were concerned about this capability, because “most dangerous of all, say Soviet tacticians, is the enemy’s ability to deliver mines remotely, right into the depths of the attacking forces.” These systems had self-destruct mechanisms and were generally used in a mixed delivery of anti-personnel landmines and antitank mines. Indeed, GATOR contained a mix of anti-personnel landmines and antitank mines.

During Operation Desert Storm the United States employed “117,634 self-destructing/self-deactivating landmines, mostly from airplanes, in Kuwait and Iraq,” its last large-scale use of mines. Reflecting on their use, retired Lt. Gen. Robert G. Gard, Jr. believed they were “   ‘counter-productive’ because the mines ‘impeded the maneuverability of our attacking units, slowed their operational tempo and inflicted casualties on our own troops.’” The adversary that framed Gard’s perspective was the Iraqi Army in a defensive posture against a rapid U.S. 100-hour ground war. In the RAND Baltic tabletop wargames, NATO forces were on the receiving end of such a rapid advance by Russian forces, who overran in the Baltics in 60 hours or less. Slowing, disrupting, and destroying such an advance is therefore a reasonable rationale for why U.S. forces need cluster munitions and mines. They are also important for attacking area systems, e.g., artillery and air defense, many of which are highly mobile and arrayed over large areas for protection.

Tactical, lower-yield nuclear weapons might also be an important component of a deterrence regime. The absence of land-based, in-theater tactical nuclear weapons leaves the United States with few rungs on the escalatory ladder between conventional and strategic options. The Nuclear Posture Review’s recommendations for U.S. nuclear modernization are a promising start, but they do not address land-based, in-theater systems. These in-place capabilities could be central, as they were during the Cold War, to deterring aggression or keeping conflict below the nuclear threshold.

New Policies and Capabilities

Two key aspects (blunt and surge) of the National Defense Strategy “Global Operating Model” require a military that can “delay, degrade, or deny adversary aggression” and “surge war-winning forces and manage conflict.” The first step in preparing the U.S. military for these missions is to examine policies to ensure the United States is in fact preparing for the present and the future, not a less-contested past. Based upon the new adversaries the United States is likely to face, the new cluster munitions policy may seem like a good first step in the right direction.

Even if policymakers were to choose to do so, reversing course on key arms limitations treaties and policies would be difficult. Nevertheless, cluster munitions, anti-personnel landmines, and tactical nuclear weapons might well be militarily necessary to deter or defeat aggression, for instance in a Baltic state invasion or Korea scenarios. And if policymakers choose to lift these bans, then the ensuing policy restrictions might be tailored to address where these capabilities are necessary. In the words of American Civil War Gen. William T. Sherman, “War is cruelty, and you cannot refine it.” It is worth examining whether not having the requisite capabilities in the U.S. military could actually prolong conflicts at horrible cost to soldiers and civilians alike.


David Johnson is a retired Army colonel. He is a Principal Researcher at the RAND Corporation, an Adjunct Scholar at the Modern War Institute at West Point, and an Adjunct Professor at Georgetown University.

Image: U.S. Air Force