Boundaries of the Battlefield Symposium Insight

Boundaries of the Battlefield Symposium Insight

[Peter Margulies is a Professor of Law at the Roger Williams University School of Law focusing on the balance of liberty, equality and security in counter-terrorism, and author of Law’s Detour: Justice Displaced in the Bush Administration (NYU Press 2010).]

The days of Donald Rumsfeld chiding “Old Europe” are gone, but targeted killing has renewed debate on counter-terrorism strategies between the US and Europe.  Boundaries of the Battlefield, a symposium sponsored last week by The Hague’s Asser Institute and coordinated by Asser researcher and Opinio Juris contributor Jessica Dorsey, offered an opportunity to explore those differences and find common ground.  The symposium, co-sponsored by the International Centre for Counter-Terrorism, IHCL Platform, Konrad Adenauer Foundation, City of The Hague, and the Dutch Foreign Ministry, was especially valuable against the backdrop of former UK Legal Adviser Daniel Bethlehem’s new AJIL piece (see Ashley Deeks’ discussion here) on self-defense against non-state actors.  This first post will flag the debate at the conference on targeted killing and what Ken Anderson has called “naked self-defense.” A second post (posted over at Lawfare) analyzes another issue that has roiled relations between the US and its allies: the clash between the law of armed conflict (LOAC) and international human rights law (IHRL).

The targeted killing debate started with law on the initiation of hostilities, aka the jus ad bellum.  In Daniel Webster’s 1841 Caroline formulation, the use of force in self-defense requires an imminent threat.  A number of conference participants, supporting the position taken by Bethlehem, favored a broad view of imminence.  I argued that the agility and clandestine nature of terrorist groups precluded waiting until the precise moment before an expected attack.  Rather, responses to violent non-state actors may appropriately trade off imminence and probability, intervening at an earlier stage to address what Chris Slobogin has called the “ideological intransigence” that make terrorist groups so difficult to combat.

However, other participants, such as Germany’s Dieter Fleck, co-editor with the University of Amsterdam’s Terry Gill of The Handbook of the International Law of Military Operations, warned against broadening imminence.  Skepticism crystallized around Bethlehem’s assertion that a potential victim state could invoke imminence if it knew that an attack of some kind was imminent, without knowing the plot’s nature or location.  Noam Lubell of the University of Essex contended that this gloss would render imminence meaningless.

Marko Milanovic of the University of Nottingham, who has written insightfully on norm conflicts in international law, targeted Ken’s “naked self-defense” argument.  Ken’s view, in its broadest iteration, holds that the US may target members of Al Qaeda anywhere on the globe, even if their presence in a particular state is fleeting, casual, and unconnected with an ongoing armed conflict.  This account was critiqued at the conference by a number of scholars, including Emory’s Laurie Blank (see here for a more comprehensive discussion), the University of Amsterdam’s Gill, and the University of Geneva’s Marco Sassoli.  Sassoli, who defined terrorism for LOAC purposes here, proposed a hypothetical, in which a member of Al Qaeda traveled through Dubai.  Most of the audience believed that the individual’s connection with Dubai was too tenuous to justify targeting.  In a vivid metaphor, Milanovic described “naked self-defense” as a “vegetarian alligator,” implying that the term was anomalous on its face.  Not to be outdone in the metaphor department, Professor Gill referred to naked self-defense as a “carnivorous hamster.”

The weapon of metaphor is a double-edged sword, and Ken’s critics may have attacked a straw man.  It’s true that Ken has suggested a heightened role for self-defense outside of the context of a demonstrable armed conflict.  However, Ken has also argued that because of the activities of Al Qaeda in the Arabian Peninsula (AQAP), the US is engaged in a non-international conflict in Yemen, site of many drone attacks.  If Ken is right about this sentiment, shared by Bobby Chesney and the US Naval War College’s Mike Schmitt, then occasions where the naked self-defense argument is a necessary justification for US action drop precipitously.  Moreover, US officials such as Eric Holder, Harold Koh, John Brennan, and Steven Preston who have spoken in public about the US position have typically acknowledged, as Brennan put it, that “international legal principles, including respect for a state’s sovereignty and the laws of war, impose important constraints on our ability to act unilaterally – and on the way in which we can use force – in foreign territories.”  This more circumscribed view does not trigger the risk of “war everywhere” that US critics fear.

Symposium participants also debated the definition of an armed conflict, including the scope of criteria like the intensity of violence and organization of the parties.  I suggested that AQAP’s activities in Yemen, including attacks in the United States coordinated by Anwar Al Aulaqi such as the Fort Hood shootings, amounted to a separate armed conflict with the United States.  As I suggested in a recent paper, this broader view of the intensity of violence tracks the jurisprudence of the International Criminal Tribunal for the former Yugoslavia (ICTY), which has found that defendants responding to alleged terrorist attacks committed war crimes if they failed to observe the principles of distinction and proportionality.  However, Milanovic and other scholars, including the European Council of Foreign Relations’ Anthony Dworkin, rejected this flexible view, claiming that it could permit states to use the targeting prerogatives of LOAC on ordinary crimes.

The audience was more willing to concede another of Bethlehem’s points, developed at length by Deeks – that a victim state may cross a border to respond to non-state actor violence emanating from the territory of a second state that is unwilling or unable to eject or neutralize the offending group.  Bethlehem, echoing Deeks’s argument, agrees that the “territorial state” must be given an opportunity to live up to its sovereign obligations.  However, if the state fails to avail itself of this opportunity, many (but not all) of those in attendance believed that the victim state had to be able to resort to self-help to address the threat.  I suggested that one factor for both armed conflict and the “unwilling or unable” test is a terrorist group’s physical footprint in a given country.  A training camp, for example, allows a group to move personnel and other assets to a “hot battlefield.”  This might be the case in Somalia, which is across the Gulf of Aden from Yemen.  According to Dan Klaidman’s book, Kill or Capture, US officials believe that AQAP is using Somalia as a training ground in conjunction with elements of the Somali Shabab organization, which has also sworn an oath of allegiance to core Al Qaeda.  Indeed, US targeting in practice has often coincided with the presence of training camps, starting with the cruise missile attack authorized by President Clinton on Afghanistan in 1998.

The awkwardness of calling a conflict that crosses borders a noninternational armed conflict (NIAC), as the Supreme Court did in Hamdan v. Rumsfeld, led Geoff Corn and Eric Jensen to call for a new category, transnational armed conflict (TAC).  While the Hague conference participants appreciated TAC’s adaptability to the conflict with Al Qaeda, they were reluctant to abandon the NIAC concept.  Wolff Heintschel von Heinegg, currently the US Naval War College’s Stockton Professor and a co-drafter of the Talinn Manual on cyberwarfare, cautioned that the temptation to embrace new categories might undermine the entire LOAC structure, which has constrained the dogs of war for over a century and a half.  Others pointed out that while NIAC has roots in the Geneva Conventions, TAC’s pedigree is more limited.   However, TAC nonetheless had significant influence for many attendees, encouraging a more flexible interpretation of LOAC criteria in the same way that the existence of any bold new alternative can galvanize reform of the status quo.

Beyond the existence of an armed conflict, scholars from Europe had concerns about the compliance of the US drone program with jus in bello rules such as distinction and proportionality.  A number focused on so-called signature strikes, noted by Dan Klaidman in his recent book.  Signature strikes occur when US drone operators detect individuals whose identities are not known to the US.  The activities of these individuals, observed by a hovering drone over twenty-four to thirty-six hours, track the activities of confirmed terrorists.  Those activities might include participating in weapons training, conducting patrols, or preparing for attacks with identified members of Al Qaeda or the Taliban.  As Mike Lewis of Ohio Northern explained, drone operators use extensive data-gathering capabilities to inform an initial judgment about whether the observed individuals’ “pattern of life” or “behavioral signature” makes them a lawful target.  That judgment is reviewed by layers of lawyers (see Greg McNeal’s paper) who also offer guidance on minimizing collateral damage.  Given the degree of care taken in targeting, drone operators’ lack of knowledge of a target’s name does not vitiate compliance with the duties of distinction or proportionality.  The US success in lowering civilian deaths (seven in 2012, down from 68 in 2011, according to the anti-drone Bureau of Investigative Journalism) demonstrates that Koh, Brennan, and other American officials have followed through on their public declarations of US compliance with in bello rules.

Critics of US policy, including the ACLU’s Hina Shamsi, who spoke at the Hague symposium, also seek more transparency from the US on targeting factors.  Critics seeking greater transparency are not wrong to seek this information – as Jack Goldsmith observed in Power and Constraint, NGO advocates perform a valuable function by pushing for openness.  However, as Mike Lewis reminded the Hague conference, the public interest may require tempering transparency.  Providing a comprehensive public account of targeting criteria may allow targets to game the system by pitching their conduct at a level just below the criteria’s reach.  Officials act responsibly when they refuse to give terrorists this sort of roadmap.

In sum, Boundaries of the Battlefield produced a robust exchange on the virtues and limits of US counter-terrorist targeting.  Many on both sides of the Atlantic critiqued the broadest account of US strategy and worried about its precedent for other nations.  However, a substantial number of the participants believed that some measure of flexibility in LOAC was necessary to meet the challenge of terrorism.

Print Friendly, PDF & Email
Events, Foreign Relations Law, National Security Law
Notify of

Thanks for the summary!  But, eeegaaads, I hope that no one used the phrase “imminent threat” because a “threat” that is imminent is not even a present threat! Therefore, use of such a criterion would be legal nonsense.  Perhaps what many mean is threat of imminent attack.
And, eeegaaads, I hope that no one thought that the Caroline incident involved a claim of anticipatory self-defense with respect to an alleged threat of imminent attack BECAUSE it is otherwise well known that the vessel Caroline had already aided insurgents who were already attacking the British-Canadian government.  The Caroline debate was all about limits of the right of self-defense against non-state actors who were engaged in continual armed attacks and opereating partly from and being supplied from another state (the U.S.) and, I still can’t find the exact cite, one of the British negotiators had written that all had agreed that if an artillery battery controlled by the insurgents or their symps was firing from the U.S. into Canada, that the British would be able to take it out as a matter of self-defense.  Re: the Caroline, please see  article at pp. 241-244.

Tamás Hoffmann
Tamás Hoffmann

“The awkwardness of calling a conflict that crosses borders a noninternational armed conflict (NIAC), as the Supreme Court did in Hamdan v. Rumsfeld, led Geoff Corn and Eric Jensen to call for a new category, transnational armed conflict (TAC).”
Most authors don’t use the term ‘transnational armed conflict’ as a new normative category but merely as a description of situations where an armed conflict involving a non-state actor crosses boundaries.
See e.g. my piece
but many other scholars such as Kress, Sassoli or Bartels use it similarly.

Remy Jorritsma

Caroline was about necessity as a justification, rather than for self-defence (cf. Commentaries to ILC Articles on State Responsibility). Why use Caroline (pre-1928, when waging war was seen as sovereign entitlement for every state) as authority for self-defence against non-state actors when the case did not concern a claim of self-defence?  

Benjamin Davis
Benjamin Davis

“The audience was more willing to concede another of Bethlehem’s points, developed at length by Deeks – that a victim state may cross a border to respond to non-state actor violence emanating from the territory of a second state that is unwilling or unable to eject or neutralize the offending group.  Bethlehem, echoing Deeks’s argument, agrees that the “territorial state” must be given an opportunity to live up to its sovereign obligations.  However, if the state fails to avail itself of this opportunity, many (but not all) of those in attendance believed that the victim state had to be able to resort to self-help to address the threat.” “Had to be able to resort to self-help” sounds in power politics to me rather than law as does the “unable or unwilling” phrase.  All of the temporal aspects of this formulation appear to be judged through the eyes of the victim state seeking to do self-help measures.  One state’s “too quickly” is another state’s “not quickly enough.”  This temporal problem nags at me and I think is what makes me hesitate to talk of these things as legal rules but more as rationalizations jus ad bellum for armed attack on the non-state… Read more »


RJ1983: you should read the exchanges between the U.S. and the U.K. as well as the full (not partial) oft-quoted phrase from Webster. These are available on-line through Yale Law library, etc., etc.  It WAS all about “self-defense” against non-state actor armed attacks!  The reference to necessity was not as an excuse for the use of armed force as such, but as a limit of the method and means of self-defense, esp. when the U.K. could have waited for the vessel to enter Canadian waters during the early 19th Cent. As I note in the article, Webster actually claimed a more significant limit re: method and means than the present use of the principle of proportionality requires, but in context the Brits could have waited until the vessel entered Canadian waters.


[…] from both sides of the Atlantic on targeted killing. I blogged about this the other day at Opinio Juris.   A blue-chip roster of participants at the conference, co-sponsored by the International Centre […]