The Shadow of Success: How International Criminal Law Has Come to Shape the Battlefield

by | Apr 5, 2023


The rise of international criminal law (ICL) and its expansion in the past few decades has been celebrated as one of the greatest achievements of modern international law, advancing justice and the rule of law, deterring atrocities, and protecting victims worldwide. In particular, for those who are concerned with the regulation of warfare, ICL, through its war crimes arm, has undoubtedly contributed to the development and enforcement of international humanitarian law (IHL).

Yet, there are also important and oft-overlooked ways in which it has done the opposite. It is these under-appreciated risks that the success of ICL has generated for IHL that I highlight in this article.

The Success of ICL

In a nutshell, my argument is that, by specifying and labeling certain violations of the laws of war as “criminal” and setting up dedicated mechanisms for prosecution and punishment of individuals responsible for these violations, the content, practice, and logic of ICL are displacing those of IHL. With its doctrinal precision, elaborate institutions, and the seemingly irresistible claim of political and moral priority, ICL – which focuses on the most highly culpable forms of misconduct within military conflicts – is overshadowing the more diffuse, less institutionalized, and more difficult to enforce general IHL.

Numerous military manuals now routinely refer to the Rome Statute (which defines the particular crimes that comprise the ICL) in expounding the IHL rules with which they are ostensibly concerned, as did the International Committee of the Red Cross in its comprehensive study on customary IHL. Reference to the Rome Statute is also routine in UN Reports, countries’ statements, and NGOs’ reports. Both scholars and legal advisors – often in search of any positive-law source to stick their teeth in – refer to legal judgments by criminal tribunals to interpret the rules of IHL and to counsel military forces on rules of engagement. Popular media pays much more attention to “crimes” than “violations,” and often frames its coverage of salient events around the criminality of the relevant conduct. Quietly, lawyers, courts, and commentators sometimes seem to accept, if only tacitly, that criminal wrongdoing dominates the field; that it is not only supreme but effectively exhausts the category of impermissible conduct in war. What is criminal is now defining both what is unlawful as well as lawful on the battlefield.

Worrisome Effects

The displacement, or overshadowing, of IHL by ICL is not merely a conceptual mistake; it poses a serious obstacle to the attainment of the very humanitarian values that ICL seeks to protect. Consider the fact that in many wars fought today, the majority of civilian deaths and injuries does not result from acts that could be classified as war crimes (even though some undoubtedly could), but from the more “mundane” choices of means and methods of warfare that at most would amount to violations of IHL. For these more routine battlefield decisions, the exact contours of any prohibition become key.

Take, for instance, the principle of proportionality: Military manuals routinely refer to the principle under the standard that would trigger individual criminal liability (provided for already in the Grave Breaches regime of the Geneva Conventions and further constricted under the ICC Rome Statute). But why is individual criminal liability the correct standard to apply when considering how a State – and its armed forces – should interpret the requirements of the principle of proportionality more generally? More worrisome yet, given the great reluctance by criminal tribunals to find culpability in allegations of violations of the proportionality principle, the conflation of the IHL standard with its criminal counterpart leaves the vast majority of targeting decisions legally unregulated.

Or take the duty to refrain from targeting where there is doubt about the legitimacy of an intended target. IHL forbids targeting where there is doubt about the status of the target as civilian or military, but it does not specify the level of doubt that requires holding one’s fire. By contrast, the prosecution of war crimes is required to meet high burdens of proof of knowledge and intent, bringing the standard closer to “near certainty” or “beyond a reasonable doubt” rather than a reasonable suspicion as to the target’s legitimacy. The consequence is, in some sense, a reversal of the rule: instead of an IHL presumption of civilian status, which gives way to targeting only where there is little or no doubt that a person or object is a legitimate military target, ICL, in effect, permits targeting up until the point there is little or no doubt that the person or object is a civilian. Some military manuals, such as the UK one, have gone in the direction of ICL, setting the bar at the very high threshold of “substantial doubt” (para. 5.3.4).

Similar doctrinal overshadowing takes place with regard to the standards of permissible environmental harm that results from military operations, or the status of children as direct participants in hostilities. In all these contexts, the contours of permissible conduct have been drawn (or run the risk of being drawn) in reference to the more-difficult-to-establish standards of individual criminal liability, as opposed to broader notions of State responsibility under IHL. And for that reason, they leave more battlefield choices under fewer legal limits.

A Double-Edged Sword

If I am correct in this analysis, war crimes jurisprudence is a double-edged sword: both an aid to the cause of humanitarianism in war, but also at times a convenient excuse for not doing more. The doctrinal precision of ICL has substituted for a more elaborate and collaborative discussion, especially at the inter-State level, over the desirable interpretation and application of IHL in military engagement. (Since 1977, there have been few, if any, successful efforts to negotiate and agree upon additional rules of IHL or to come to a common understanding of existing ones.) Instead, each State in effect decides for itself which if any IHL obligations (apart from ICL obligations) constrain its military.

No less importantly, ICL has focused our attention on individual trials of perpetrators of the most egregious offenses, allowing States to avoid their obligations – which are almost never fulfilled in practice – to account for their responsibility for general IHL violations, including by making reparations. This failure to make reparations is both on the part of individual States and the international community writ large: There have been virtually no efforts to set up a mechanism for the determination and payment of reparations for cases of IHL violations.

Concluding Thoughts

My point is not to indict ICL as a project, nor to minimize the many ways in which it has strengthened the legal protections of victims of misconduct in war. Rather, it is to urge care and precision when one borrows from one field and transfers to the other. Military legal advisors, in particular, should be particularly diligent in making sure that their counsel to the armed forces is not limited to the avoidance of criminal charges, but instead is faithful to the broader requirements of IHL.

More ambitiously, and especially against the background of the raging conflicts in Europe, the Middle East, and north Africa, perhaps it is time to borrow the multilateral process of modern ICL and think about mechanisms for further negotiations and agreement over the interpretation, application, and enforcement of IHL rules.


Gabriella Blum is the Rita E. Hauser Professor of Human Rights and Humanitarian Law, and the Vice Dean for the Graduate Program and International Legal Studies at Harvard Law School.



Photo credit: Pexels