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Yemen, international law, war crimes

Can Weapons Manufacturers be Held Responsible for War Crimes?

Convicting weapons manufacturers as war criminals could help end the war in Yemen.

Words: Jake Romm
Pictures: Matthew Henry

Since 2015, Saudi Arabia has been conducting airstrikes in Yemen as a part of its intervention into the country’s brutal civil war. And since 2015, these airstrikes have killed numerous civilians and destroyed or damaged critical civilian infrastructure. As legal scholars, international bodies, and nongovernmental organizations have asserted, many of these strikes are almost certainly war crimes.

But despite the almost routine criminality of Saudi Arabia’s bombing campaign in Yemen, US-made weapons continue to flow, and US weapons manufacturers continue to profit off the death they help produce. Indeed, as Responsible Statecraft reported, Raytheon CEO and Chairman Greg Hayes appeared to “celebrate a potential war over Ukraine and Houthi drone attacks on the UAE as good indicators for future weapons sales” in a January 2022 earnings call.

While executives from other arms manufacturers made similar remarks during the earnings call, I mention Raytheon in particular because Raytheon-manufactured weapons have been used in Saudi mass-civilian casualty strikes with unnerving frequency. Most recently, Amnesty International reported that Raytheon had manufactured the bomb used “on a detention center in Sa’adah, northwestern Yemen, which, according to Doctors without Borders, killed at least 80 people and injured over 200.” Even though Saudi Arabia bears primary responsibility for criminal strikes, such as the one in Sa’adah, Hayes may also bear criminal responsibility as an aider and abettor.


There is a long history of convicting corporate actors as aiders and abettors in international criminal law dating back to the post-World War II trials. In the Trial of Bruno Tesch and Two Others (“Zyklon B” Case), three defendants were charged by a British tribunal with aiding and abetting the murder of “Allied nationals” by supplying the SS with Zyklon B, the chemical used in the Nazi gas chambers. Two of the three defendants were convicted on the theory that they supplied the means for the commission of the offense (the actus reus, or action) and that they “knew that the gas was to be used for the purpose of killing human beings” (the mens rea, or mental state). Similarly, in the Trial of Friedrich Flick and Five Others, an American tribunal convicted two former Nazi industrialists of financial support to a criminal organization (i.e., aiding and abetting) for contributing money to the SS. The two were convicted under the theory that “One who knowingly by his influence and money contributes to the support thereof must…be deemed to be, if not a principal, certainly an accessory to such crimes.”

The knowledge mens rea standard set by these cases — a defendant need only know that their aid would in some way contribute to the principal crime — was followed as well by the International Criminal Tribunal for the Former Yugoslavia (ICTY), the International Criminal tribunal for Rwanda (ICTR), and the Special Court for Sierra Leone (SCSL). Under the International Criminal Court’s Rome Statute — the only operating international criminal law instrument with potential applicability to the Yemen conflict — however, aiding and abetting liability only kicks in if a person renders aid with the purpose of facilitating the underlying crime.

This purpose requirement introduces a more stringent mens rea than the knowledge requirement of the post-World War II trials, and the element becomes even more difficult to prove in the case of corporate actors. Corporations have one underlying motivation: to make money. Thus, Hayes could reasonably and convincingly say that only the reason Raytheon rendered aid to Saudi Arabia was to turn a profit, and so what the Saudis do with it is their business. Such a strict interpretation of the Rome Statute would, however, seem to foreclose the possibility of ever convicting a corporate actor for aiding and abetting. Fortunately, “purpose” is not as restrictive as it seems.


In a 2008 article for the Northwestern Journal of International Human Rights, Professor Doug Cassel of Notre Dame Law School offers a novel and useful interpretation of the Rome Statute’s “purpose” requirement. He writes, “‘purpose’ in the ICC Statute need not mean the exclusive or even primary purpose. A secondary purpose, including one inferred from knowledge of the likely consequences, should suffice.” Cassel uses the Zyklon B case as an example, writing that if Tesch’s primary purpose was to make a profit by selling Zyklon B, one could infer from his knowledge of how the SS was using the Zyklon B that his secondary purpose was to encourage mass murder. That is, “if Hitler were to cease gassing Jews, the Nazis would no longer buy so much gas.” As Cassel writes, if the object and purpose of the Rome Statute is to ensure that “the most serious crimes of concern to the international community as a whole must not go unpunished,” it is “difficult to believe that the drafters would have intended that those who knowingly supply gas to the gas chambers, for the primary purpose of profit, should escape punishment.”

At the first glance, the idea of secondary purpose sounds almost identical to a knowledge standard, but it can be distinguished by flipping the aider–principal relation on its head. If, as Cassel explains about the Zyklon B case, Tesch’s primary purpose was to make a profit and his secondary purpose was that the gassings continue so that the Nazis would continue to purchase Zyklon B in such high quantities, then we can say that the secondary purpose had a causal relationship with the primary purpose. That is, the criminal action of the secondary purpose (murder) promotes or furthers the primary purpose (profit), much in the same fashion that, for the principal, the rendered aid promotes the primary criminal purpose.

While international criminal law may be a poor tool with respect to garnering a conviction here, it is not a conviction that should be the primary goal; it is an end to the war, and an end to impunity for those trafficking in death.

We can add to this an even higher level of causal connection (a necessary relationship), one in which the criminal action (the secondary purpose) is the sole cause of the primary purpose’s success. In the Zyklon B case, this necessary relationship between the primary and secondary purposes would appear if the only reason that the SS ever purchased Zyklon B in such numbers was for its use in the gas chambers. That is, Tesch, in order to achieve his primary purpose of making a profit, must have also acted with the secondary purpose of facilitating murder because it is only because of this murder that he was able to sell Zyklon B in the first place. With either the necessary relationship or even the lesser causal relationship in place, one could infer that Tesch acted with the purpose to aid in the crime of murder because the secondary purpose is either what made the primary purpose possible in the first place (thus rendering them inextricable) or facilitates the success of the primary purpose.

With respect to Raytheon’s criminal responsibility in Yemen, an isolated incident of its bombs being used to kill or harm civilians is one thing, a pattern is another. Saudi Arabia’s intervention has been marked by such widespread and publicly known criminality, largely facilitated by Raytheon munitions, that it would be unreasonable for Hayes to claim that he did not have the knowledge that arms sold to the Saudis would be used for a criminal purpose and that he did not act with a secondary purpose of facilitating the Saudis’ criminal bombing campaign. On top of that, as Hayes’ remarks at the investor call makes clear, war is good for business, and the Saudi war on Yemen is particularly good (by October 2018, sales to Saudi Arabia constituted 5% of total revenue for Raytheon for that year alone). This is as clear an illustration of the idea of secondary purpose as one could ask for: If Saudi Arabia were to cease its criminal intervention in Yemen, it would no longer buy so many bombs. What’s more, the destabilization caused by the criminal nature of the war only serves to draw it out, increasing both human misery and Raytheon’s profits in direct relationship. While seemingly short of a necessary relationship, Saudi criminality and Raytheon profits appear to exist in a sufficiently causal relationship to pass this primary-secondary purpose test.


All that being said, it would be unwise for people to hold their breath for a criminal conviction, or even a charge. No international court currently has jurisdiction over the situation in Yemen, and we should not be so naive as to think that the US or any other country will convict, let alone bring charges against Hayes, who stands atop one of the giants of the military-industrial complex.

Furthermore, even if a conviction were plausible, the legal form, focused is it is on individual perpetrators and individual instances of criminality, cannot address the underlying causes and ongoing horrors of the Yemen conflict writ large, and indeed, risks obscuring those causes, subordinating them to the symptomatic manifestations of violence. As legal scholar Tor Krever writes: “in the case of international criminal law, the preoccupation remains with the abnormality of conjunctural violence, rather than with the normality of the forces — including economic and legal structures — that lurk beneath.”

Laying out the legal argument against Hayes, however, can lead to a denaturalization of arms sales — so routine and integral to the US global presence — and, in turn, help provide the language required for political pressure. Thus, while international criminal law may be a poor tool with respect to garnering a conviction here, it is not a conviction that should be the primary goal; it is an end to the war, and an end to impunity for those trafficking in death. And one step we can take to help curb the bombings and hasten Saudi Arabia’s exit from the conflict is to call those who deal arms to the Saudis by their proper name — that is, war criminals.

Jake Romm is a graduate of the University of Pennsylvania School of Law and a former legal fellow at Reprieve US where he worked on Guantanamo Bay and the detention of foreign nationals in northeast Syria. His writing can be found in Opinio Juris, The International Criminal Law Review, Hyperallergic, The New Inquiry, and other publications.

Jake Romm

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