Battlefield Detention, Counterterrorism, and Future Conflicts


| Mar 24, 2021

Battlefield Detention. Hedi-benyounes-unsplash

Editor’s note: The following post is part of the Articles of War Symposium on Beth Van Schaack’s book, Imagining Justice for Syria. The symposium offers a platform for the contributing experts to carry the conversation on justice and accountability in Syria forward.

Battlefield detention involves many complex issues. Most notable among these is the challenge of providing effective, durable disposition options for detained terrorists. Because battlefield detention is, with very few exceptions, transitory in nature, it is imperative that those engaging in conflict be prepared to support eventual disposition options such as criminal prosecution, rehabilitation, or even release. On that score, we need to learn from the past and to remember lessons learned on the battlefields of Iraq and Syria. This post will revisit those lessons and conclude by offering six factors that should be taken into consideration when planning for future conflicts.

The Detainee Situation in Syria

In her recent book Imagining Justice for Syria, Professor Beth Van Schaack notes the detention of large numbers of Islamic State of Iraq and Syria (ISIS) foreign terrorist fighters by the Syrian Democratic Forces—the non-State armed group “comprised mainly of Kurdish militias.” In commenting on their continued detention, Professor Van Schaack underscores the inability of the Syrian Democratic Forces to “undertake detention operations in compliance with international humanitarian law or to conduct fair criminal trials where warranted.”

The problem Professor Van Schaack highlights came into sharp focus in the waning months of 2017, as the self-proclaimed ISIS caliphate fell into ruinous defeat, and the United States and coalition forces began to grapple with many significant remaining post-conflict challenges. Among these were problems associated with the “human debris” who were left in the detritus of the crumbled caliphate.

The continued detention of these terrorists in such conditions was (and remains) a problem on many levels. Previous counterterrorism experience has shown that terrorists cloistered in detention facilities for a prolonged period of time can grow more extreme, more networked, and more lethal. After all, it is now understood that the leadership of ISIS—including Abu Bakr al-Baghdadi—evolved in the confines of a U.S. detention facility in Iraq. Moreover, in Syria, the fact that these ISIS fighters are detained by a non-State armed group—without the organic capacity to hold prisoners for long periods—has raised the concern of their possible release. On September 24, 2019, in remarks given to an array of governments at a multinational counterterrorism forum, U.S. Ambassador Nathan Sales succinctly stated the problem: “We applaud the SDF’s capture and detention of these dangerous individuals and their associated families. But we are deeply concerned about our partners’ capacity to detain this massive population indefinitely. Critically, we seek to prevent seasoned fighters from returning to the battlefield.”

The conflict in Syria was obviously not the first time that the United States or its coalition partners had faced this set of challenges. The problems associated with battlefield detention are as well-known as the universe of rules that govern it. Military manuals teem with explanatory text describing who can be detained during an armed conflict, how detainee operations should be carried out, how detainees are to be treated, etc.

Depleted ink, however, is obviously insufficient to internalize important lessons. Recent history demonstrates that the United States and our coalition partners, due to an amnesiac, Sisyphean policy and planning approach to detention operations, seem condemned to repeat the same mistakes, relearn the same lessons, waste resources, and court disaster. Breaking from this pattern and integrating lessons learned from previous experience with battlefield detention will be increasingly important to success in future conflicts (especially counterterrorism operations). As the conflict in Syria has highlighted, the inability to properly plan for detention operations is acutely exacerbated in the context of modern counterterrorism efforts in which U.S. and coalition forces find themselves working “by, with, and through” a non-State armed group.

Battlefield Detention and its Outcomes

The Transitory Nature of Battlefield Detention

Battlefield detention is a general term used to describe the detention of persons captured or otherwise taken into custody by military authorities during the course of an armed conflict and held without trial. There are myriad legal bases for detaining persons under such circumstances, and varying categories of detainees are deeply inscribed in international law. No matter the legal basis or characterization of the detainee, however, an important and immutable quality of battlefield detention is that it is inherently temporary. Otherwise stated, with few real (and costly) exceptions, battlefield detention is not a final disposition option, but a mere interim state of affairs.

There are legal reasons for the transitory character of battlefield detention. The same law of armed conflict that permits battlefield detention also regulates and curtails its use. Importantly, international law restricts the length of time for battlefield detention. Most significantly—though different legal regimes will apply in international and non-international armed conflicts—as a general matter, under the law of armed conflict, the end of hostilities will mark the outer valence of permissible detention of foreign terrorist fighters detained during counterterrorism operations, beyond which some other legal basis for detention would be required (such as a criminal prosecution). The U.S. Supreme Court highlighted this rule in Hamdi v. Rumsfeld when it noted a “clearly established principle of the law of war that detention may last no longer than active hostilities.” Thus, whether the individual in question is captured in an international or non-international armed conflict, battlefield detention has (at least in theory) a temporal limit. Though this legal/temporal requirement has been stretched during the current era of “long wars” such as the Global War on Terrorism, it remains a significant constraint that looms over every aspect of detention operations.

Beyond those legal requirements, there are also very practical reasons why battlefield detention is only an interim detention mechanism. One principal reason is its expense. Battlefield detention is a costly endeavor. Detention operations require guards, food, housing, personnel to conduct medical screening and treatment, legal support, appropriately trained interrogators, etc. The circumstances of detention must be sufficient to comply with international legal norms. These conditions require funding and frequently require reallocation of resources from other parts of ongoing operations. Using Iraq as an example, it was estimated that the U.S. detention program cost approximately $500 million a year. When factoring in the additional costs of attendant institutions such as courts and critical parts of the justice sector, the costs quickly increase. It is, therefore, not something that can be done for a sustained period without a serious commitment of resources.

Disposition Options

Because battlefield detention is temporary, it is critical that planners and policymakers focus on the formulation of appropriate long-term disposition options for detainees and the development of efficient pathways for those disposition options. Although this is true for any country engaging in operations requiring battlefield detention, a review of U.S. doctrine addressing the topic is instructive.

Joint Publication 3-63 (Detainee Operations) describes the term “detainee disposition” as “the intended status of a detainee’s liberty, confinement, or fate upon release from DOD control.” The document provides four potential dispositions: repatriation, release, escape, or death. Release includes the possibility of release to a partner nation’s military or, importantly, “[release] to the local equivalent of law enforcement or corrections officers.” Echoing this very limited range of disposition options, the 2017 U.S. Army Operational Law Handbook notes: “In any operation, there should be a system in place ‘for the capture, evidence collection, processing, questioning, tracking, internment, prosecution, and subsequent release of captured individuals.’”

The doctrinal point is that battlefield detention is temporary and, accordingly, any plan that involves capturing and detaining enemy forces must also provide for disposition outcomes for those detained. The international recognition of this reality was recently highlighted in a February 2021 virtual meeting cohosted by the Parliamentary Assembly of the Mediterranean (PAM) and the UN Office of Counterterrorism (UNOCT) on “Challenges of the post-territorial ISIL context.” During the meeting Senator Alia Bouran of Jordan stressed the challenges of repatriation, prosecution, deradicalization, evaluating the threat of recidivism, and strengthening international counterterrorism cooperation to deal with persons detained in Syria.

The Lessons of Iraq: Insufficient Planning

The wars in Iraq required the U.S. and coalition partners to learn hard lessons about detention and the importance of detainee policy. In the initial phases of the Iraq war, the U.S. military effort suffered from inadequate pre-conflict planning to address detainee operations, including “underdeveloped doctrine that did not adequately reflect the lessons learned from previous detainee operations[,]” as well as “inadequate pre-conflict planning for handling large numbers of detainees and, on realization that a large-scale counterinsurgency was yielding a large number of detainees, difficulty in forecasting the required capacity and obtaining funds to build adequate facilities.”

Detention operations in Iraq did evolve, however, and eventually a system developed to maintain large numbers of detainees, to facilitate their interrogation, and to screen detainees for appropriate disposition options (such as to ascertain whether detainees were to be prosecuted under Iraqi law, released, or held in detention for posing a threat to security). Notably, many detainees were brought before an Iraq criminal court called the Central Criminal Court of Iraq (CCCI) for prosecution, and roughly 50-60% were convicted. U.S. Navy Captain Brian Bill highlights both the contours of the architecture that permitted criminal prosecution of battlefield detainees in Iraq (using the foundations of the existing Iraqi legal system), and the significant amount of U.S. support required for those Iraqi prosecutions, principally through U.S. personnel who were designated as CCCI liaison attorneys or “special prosecutors.”

Eventually, toward the end of the conflict, U.S. and coalition operations incorporated tactics and procedures designed to lend greater support to Iraqi judicial disposition options. Military commentators began noting the practice of “warrant-based targeting” and “conviction-focused targeting” to “build credible bases for judicially-issued arrest warrants, seek those warrants, apprehend pursuant to those warrants while collecting evidence for prosecution, then hand off apprehended individuals along with evidence collected to competent judicial and correctional authorities.” The detainee operations ecosystem evolved with the changing political realities to enable Iraqi criminal justice solutions where available.

In the end, however, the temporariness of battlefield detention could not be escaped. While there were judicial disposition options for some battlefield detainees, of the 100,000 people detained by U.S. forces between 2003-2009, the majority were released without trial. Such releases were later attempted in conjunction with local officials who facilitated reintegration efforts such as “reconciliation ceremonies” at which the former detainees were handed over to their sheik leaders who were, in turn, responsible for assisting in reintegrating the detainee into the community. The vast majority of battlefield detainees captured in Iraq, however, were released without a significant plan to track their post-release activity. By 2009, the rate of release was dramatic (over 1,000 a month). And, at the end of that year, far more were simply let go than were prosecuted.

This is certainly not to say that battlefield detention in Iraq was without value. The battlefield detentions carried out in Iraq were of great military advantage and benefitted counterterrorism efforts on several levels. Through battlefield detention, U.S. and coalition forces temporarily removed threats from the battlefield; disrupted terrorist attack planning; conducted interrogations to provide commanders (and others) with needed intelligence; and collected needed biometric data for intelligence and other lawful purposes. Battlefield detention helped to accomplish all those things, but it ultimately could not be the mechanism for the long-term incapacitation of those captured.

Thus, aside from reminding us that detention operations require intense planning and effort, the conflict in Iraq again taught us that battlefield detention is temporary—and that all the people captured and detained must eventually either be prosecuted in a criminal court or released. And, as the United States national security community learned, what happens after that moment of release will frequently depend on the quality of planning and policymaking that precede the capture.

ISIS Detainees in Syria

As noted, the Syrian Democratic Forces have detained more than 2,000 ISIS foreign fighters and have signaled that they do not have the capacity or authority for their continued detention. Moreover, the countries of origin of these captured terrorists are reluctant to accept their return, citing legal obstacles to repatriation. Although the United States and other countries have repatriated and prosecuted a small percentage of these battlefield detainees, the majority remain detained under precarious circumstances.

The United States and coalition partners have taken action to support Syrian Democratic Forces detention operations so that this awkward status quo can be sustained and marginally improved. As Professor Van Schaack notes, “The United States is funding training and infrastructure improvements, but has resisted directly undertaking detention operations in Syria given its own troubling history with law-of-war detention.” Such assistance is needed and important, but so long as real disposition options remain elusive, its effect is only to postpone the inevitable.

A key explanation of the current situation is difference between working with State actors and non-State actors. Because of this difference, the lessons of Iraq were not effortlessly exportable to the conflict in Syria. The sorts of resources, institutions, and capabilities that the United States and coalition partners were able to bring into service of detention operations in Iraq were largely unavailable working “by, with, and through” a non-State entity in Syria. For instance, although certain non-State groups in Syria “formed their own rudimentary administrative and judicial institutions,” a developed criminal justice architecture that could be augmented with U.S. support (such as the CCCI in Iraq) did not exist. Nor was there an existing prison system to facilitate detention. Moreover, the United States was not willing to adopt the open purse approach in Syria that had defined the conflict in Iraq. The same interagency tool kit and level of resources, therefore, could not simply be replicated. For this reason, Syria provided somewhat unfamiliar planning and policy terrain.

Historic patterns are a secondary reason for the current state of affairs (as the past is prologue). The United States has a perennial blind spot when it comes to planning for detainee operations. U.S. policymakers and planners consistently underestimate the size of the captured population, subsequent logistical requirements, legal challenges, and other related problems.

This lack of vision may be due to our general dislike of the idea of detention. As Benjamin Wittes notes, “The Western world does not believe in detention. Even when Western nations need detention, they do not believe in it or want to acknowledge it, and so, over the years, they have developed elaborate systems for pretending they do not engage in it.” We dislike the concept, so we forget hard lessons learned—because we want to forget them. Wittes goes on to highlight what he describes as “the Western consensus that detention should be conducted out of view and preferably by proxies,” and posits that “U.S. detention policy is moving exactly in the direction of this obfuscatory model.” This unsighted predisposition tempts officials to wash their hands of the taxing task of providing for detainee disposition outcomes, and to assume that the proxies upon whom this hard work is foisted will have the ability to figure out what to do with those they’ve captured. Such assumptions, of course, are frequently wrong.

Another aspect of the obfuscatory model Wittes describes is that it permits policymakers and planners to actively avoid thinking about what must eventually come after the moment of capture. When responsibilities are outsourced to others, the hardest aspects of the endeavor can be ignored. The silence of these post-capture lacunae lull policymakers into forgetting about battlefield detention’s relentless impermanence. We are tempted to again believe that the status quo will endure; that no moment of reckoning will come. And then it does.

With regard to Syria, the result of this confluence of factors was a relative planning and policy void. The question of what Syrian Democratic Forces partners would ultimately do with the fighters they captured and detained was largely left unaddressed. Contrary to doctrinal guidance, at the outset of the effort, no real system was ever put in place to ensure appropriate evidence collection, processing, questioning, tracking, prosecution, and subsequent release of captured individuals. The Syrian Democratic Forces simply fought, prevailed, captured the enemy, bandaged their wounds, and then asked the rest of the world what to do. The United States and others, in turn, did what they could to assist their non-State partner, but post-conflict efforts to compensate for the lack of detention architecture and disposition options were ad hoc and sporadic. As a result, they are also ongoing. Professor Van Schaack aptly sums up the current posture, noting, “Uncertainty abounds as to how to resolve this situation.”

Factors to Consider in Future Detention Operations

Milan Kundera wrote, “The struggle of man against power is the struggle of memory against forgetting.” Our ability to effectively carry out detention operations in future counterterrorism efforts will depend on our willingness to struggle against the forces that tempt us to forget what so many difficult conflicts have taught us about battlefield detention. We must also be able to further apply those lessons teleologically to new types of conflict.

Those lessons counsel that detention operations should be viewed as being as important as the kinetic operations. As such, they should be the subject of extensive advance planning. Among the myriad factors for consideration, that planning must be sure to consider the following:

1. Battlefield detention is a resource-intensive endeavor, and underdeveloped partners will require extensive support (financial support, training, etc.) to effectively carry out detention operations in a manner that comports with international legal norms.

2. Battlefield detention is temporary. As a general matter, it is not a long-term disposition outcome. It is only an interim measure pending the repatriation or release of the person detained.

a. Implementing effective pathways for the repatriation or release of the battlefield detainees requires extensive advance planning and diplomatic engagement.

3. In operations involving large-scale detention, long-term disposition options will only be available for a minority of detainees. When large numbers of people are detained, large numbers of people will eventually be released.

a. It is, therefore, critically important to have personnel and resources in place for interrogation and collection of biometric information during the period of detention.

i. This information, when appropriate, should then be shared with the intelligence, law enforcement, customs, and border security officials of partner nations.

4. Frequently—especially in the context of counterterrorism—the desideratum of battlefield detention will be a criminal prosecution in the courts of the host nation, the detainee’s country of origin, or a third country. In appropriate cases, international courts may also be a potential forum for prosecution.

a. Criminal prosecution will only be an available option for a small subset of the detainee population.

b. No matter the forum, criminal prosecutions do not happen automatically. They require admissible evidence; they frequently require the availability of witnesses; and they require the political will of a country or international entity to undertake the prosecution.

c. When working “by, with, and through” non-State partners who lack organic criminal justice institutions, policymakers and planners must commit additional resources to compensate for this dramatic institutional paucity.

i. This may mean using military personnel and/or deployed interagency personnel to create a system to enable appropriate evidence collection, processing, questioning, tracking, and the subsequent transfer of captured individuals to their countries of origin for prosecution.

d. Where the need for repatriation is envisioned, senior military and diplomatic personnel must engage with international partners in advance of the military effort to obtain their commitment to accept custody of their detained citizens.

5. Battlefield detention should always be conducted in accordance with international legal norms to mitigate against further radicalization, to ensure legal and regulatory interoperability with partner nations, and to avoid problematizing legal pathways to transfer or repatriation.

6. Battlefield detention is a complex endeavor and problems will arise. The solutions to those problems must be addressed at the outset and not hoped for in the aftermath.

The conflict in Syria has underscored the criticality of detention operations and ensuring appropriate disposition options for battlefield detainees. While detention operations are complex and expensive, they are also necessary—and, in the context of counterterrorism, the disposition outcomes of battlefield detainees can even be determinative of the ultimate outcome of the larger military effort. The lessons learned through past experiences with detainee operations, therefore, must be remembered and assiduously applied. Applying these lessons will require additional effort and resources when working “by, with, and through” partner forces (especially when those partners are non-State actors). It will also require elevating detention issues to their appropriate place in the hierarchy of national security policy priorities. As we have learned through hard experience, the outcome of our approach to battlefield detention may ultimately be the real determinant of our strategic success.


Dan E. Stigall is the Deputy Chief of Staff and Counselor for International Affairs for the National Security Division, U.S. Department of Justice (DOJ). He is also a Distinguished Professional Lecturer in National Security Law at the George Washington University Law School.


Other Posts in the Symposium

See also Beth Van Schaack’s book, Imagining Justice for Syria and her earlier Articles of War post with the same title.