[Photo credit: U.S. Department of Defense, Flickr]

To comply with the laws of war, what should a commander know before launching an attack against a military objective? How are military legal advisers interpreting, shaping, and operationalizing those standards on modern battlefields? And how are prosecutors and judges at the national and international levels defining violations of those standards?

One key and notoriously vague set of criteria relating to these standards stems from the international humanitarian law (IHL) principle of proportionality. That fundamental rule aims, in the words of the International Committee of the Red Cross’s Commentary on the law, to establish “an equitable balance between the humanitarian requirements and the sad necessities of war.” In broad terms, the IHL principle of proportionality prohibits attacks that are expected to cause incidental loss of civilian life, injury to civilians, damage to civilian objects, or a combination thereof that would be excessive in relation to the concrete and direct military advantage anticipated. Unpacking these general terms so that they can be effectively applied in combat operations raises complex interpretative challenges.

This project explores international legal standards regarding what decision-makers in the armed forces are expected to know in order for targeting decisions to be lawful. We will examine how those standards have developed over time, as well as how states are interpreting and implementing those standards today, especially in light of developments in war-fighting technologies and intelligence-gathering techniques. We will explore the potential effects on battlefield proportionality decisions of the increasingly greater and more immediate media and public scrutiny due in part to the proliferation of video-, audio-, and image-capture devices (such as smartphones). 

In the contemporary normative environment, the baseline of knowledge and the definition of a “reasonable” commander are increasingly important to identify — not only for those interpreting the law within the armed forces but also for those seeking accountability for alleged violations of the IHL principle of proportionality. We plan to pursue research questions from the perspectives of a range of actors, including military commanders, armed forces legal advisers, and prosecutors. Those questions include:

  • On the modern battlefield, how do armed forces operationalize the legal concepts of “excessive,” “concrete and direct military advantage,” and “anticipated”?
  • How do states address in their military doctrine the “delicate problem” (in the ICRC’s terminology) of identifying which situations leave no room for doubt and which situations call for hesitation?
  • How have developments in intelligence-gathering techniques, as well as weapons and other targeting-related technologies, affected interpretations and applications of these standards?
  • How have international tribunals as well as domestic military and civilian courts interpreted these knowledge standards? 

By enhancing our understanding of what international law demands of combatants when they undertake the balancing exercise at the heart of the IHL principle of proportionality, our project seeks to complement research initiatives that examine other elements of the law of targeting in armed conflict. Amid the changing character of modern wars — including non-international armed conflicts with multi-national dimensions, air warfare, and remote targeting operations — we will assess historical materials, state practice and opinio juris, military doctrine, academic writings, and international and domestic jurisprudence.

Research Assistants

Related Writings from PILAC Scholars

Professor Gabriella Blum

“The Dispensable Lives of Soldiers,” 2 Journal of Legal Analysis 69–124 (2010)

Professor and PILAC Fellow Michael N. Schmitt

Targeting: The Challenges of Modern Warfare (Paul A.L. Ducheine, Michael N. Schmitt &  Frans P.B. Osinga eds., Asser/Springer 2015)

With Eric Widmar, “On Target”: Precision and Balance in the Contemporary Law of Targeting, 7 Journal of National Security Law and Policy __ (2014)

With Christopher Markham, Precision Air Warfare and the Law of Armed Conflict, 89 International Law Studies 669-695 (2013); 43 Israel Yearbook on Human Rights 297-319 (2013)

Targeting in Operational Law, in The Handbook of the Law of Military Operations 245-275 (Terry Gill & Dieter Fleck eds., Oxford University Press, 2010)

Air Law and Military Operations, in The Handbook of the Law of Military Operations 303-323 (Terry Gill & Dieter Fleck eds., Oxford University Press, 2010)

Targeting and International Humanitarian Law in Afghanistan, in 85 International Law Studies 307-339; 39 Israel Yearbook on Human Rights 99 (2009)

Proportionate and Discriminate Use of Weapons:  Challenges for a Military Commander, 37 Collegium (College of Europe) 53-63 (2008), reprinted as The Principle of Distinction and Weapons Systems on the Battlefield, II:1Connections (PfP Consortium) 46-56 (2008)

Targeting, in Perspectives on the ICRC Study on Customary International Humanitarian Law 131-168 (Susan Breau & Elizabeth Wilmshurst eds., Cambridge University Press, 2007)

Fault Lines in the Law of Attack, in Testing the Boundaries of International Humanitarian Law 277-307 (Susan Breau & Agnieszka Jachec-Neale eds., British Institute of International and Comparative Law, 2006)

Precision Attack and International Humanitarian Law, 87 (No. 859) International Review of the Red Cross 445-466 (2005)

Targeting and Humanitarian Law: Current Issues, 33 Israel Yearbook on Human Rights 59-104 (2003); 80 International Law Studies 151-94 (2006)