Searching for a Practical Legal Test for the End of Non-International Armed Conflicts

Editors’ note: This post is drawn from the authors’ article-length work, “Establishing a Practical Test for the End of Non-International Armed Conflict” appearing in the International Review of the Red Cross.

International humanitarian law (IHL) is an exceptional body of law that applies to exceptional situations, from the onset of an armed conflict until its end. During armed conflict, IHL accepts killing, maiming, destruction of property, and deprivation of liberty that would be criminal during times of peace. It likewise authorizes or accepts, again during armed conflict, ancillary or collateral harm to civilians and civilian populations, exposing them legally and practically to violence and impositions on their rights that they would be insulated from in the absence of armed conflict.

But IHL is inherently time bound, and its acceptance of violence and the consequences of violence make questions about when armed conflicts begin and end especially important. Despite the legal significance of being able to clearly identify when armed conflicts begin and end, IHL still lacks a consensus test for determining when non-international armed conflicts (NIACs) end beyond the International Criminal Tribunal for the former Yugoslavia’s (ICTY) nearly 30-year-old admonition that IHL continues to apply to a NIAC until a “peaceful settlement is achieved.”

This lacuna is unsatisfactory. The absence of a controlling test for determining the end of a NIAC may result in the prolonged exposure of civilians to the harms intrinsic to armed conflict. It may tempt States to resist the termination of NIACs in order to enjoy IHL’s comparatively liberal use-of-force regime to broadly expose antagonists to detention or targeting. It may also benefit non-state organized armed groups (OAGs) that seek to wear down States through prolonged, armed violence that would be prohibited in ordinary circumstances. In sum, the absence of a controlling test for the legal termination of NIACs may unnecessarily prolong armed conflict’s state of exception, inhibit the restoration of peace, and prevent the resumption of ordinary domestic law and international human rights law.

In “Establishing a Practical Test for the End of Non-International Armed Conflict,” recently published in the International Review of the Red Cross, we propose a practical legal test (the “Farley-Pradhan test”) for ascertaining when NIACs terminate that incorporates existing law and attempts to account for the wide variety of factual circumstance that characterize NIACs.

We suggest that a NIAC terminates as a matter of law when:

(a) either the intensity of armed violence or the organization of a party diminishes below the threshold necessary to constitute a NIAC;

(b) for a period of at least five months; and

(c) when observable circumstances suggest that the armed conflict has terminated in fact.

Based on a review of four case studies, we believe that this fact-intensive and objective standard would be a practicable and reliable legal test for determining when NIACs end that avoids the uncertainty or impracticality embedded in other proposed tests. Additionally, we believe that this standard would cabin States’ discretion to claim a NIAC continues despite objective, observable factors.

Significantly, the standard would better facilitate the resumption of international human rights law and domestic legal regimes, even when sporadic, isolated organized armed violence or disorganized armed violence continues, as would be the case if the situation never crossed the NIAC threshold in the first place. In such circumstances, that sporadic organized or disorganized violence would appropriately be primarily regulated by domestic criminal law.

Existing Test for the Termination of NIAC

Since the ICTY decided the Defence Interlocutory Appeal on Jurisdiction in Prosecutor v. Tadić and pronounced that IHL continues to apply to a NIAC until a “peaceful settlement is achieved,” no court has determined whether or when NIACs conclude as a matter of IHL. In the face of that judicial silence, scholars have developed four competing tests to ascertain whether or when a peaceful settlement of a NIAC has been achieved, none of which has become widely accepted. They include: a Reverse Tadić test; a No-More-Combat-Measures test; a Peaceful Settlement test; and a No-Reasonable-Risk-of-Resumption test.

The Reverse Tadić test ties the legal conclusion of a NIAC to the diminution of one of the Tadić test’s constituent conditions, either intensity of violence or organization of the parties, below the threshold at which hostilities would be established. This test, however, does not provide sufficient certainty when NIACs ebb and flow, as many do, giving rise to the so-called revolving door problem of conflict classification.

The No-More-Combat-Measures test connects the end of a NIAC with the end of military operations. However, this test may not be clearly applied when multiple groups are involved in a NIAC. And States in particular may be incentivized to refrain from announcing an end of military operations in order to benefit from relatively looser targeting and detention standards under IHL. It may also cause the prolonged application of IHL to an erstwhile situation of armed conflict beyond the diminution of hostilities below the Tadić threshold, while a party’s armed forces continue to mount military operations.

The Peaceful Settlement test relies on States and non-State parties being willing to enter into negotiations and successfully conclude hostilities. However, reduction of violence below the Tadić threshold and dismantling of parties may be objectively observable even without a political settlement, and the termination of a NIAC should not therefore depend on such a condition. This test is especially problematic in situations in which a party refuses to engage in negotiations with its adversary, thereby preventing the test’s satisfaction.

The No-Reasonable-Risk-of-Resumption test requires evaluation of whether it would be unreasonable to believe that hostilities could resume. This test may include assessment of the amount of time passed since hostilities took place, along with statements made by the parties and actual steps taken to end the conflict. But its reasonableness standard may be difficult to apply in practice because it is open ended. It may also lead to uncertainty as observers disparately interpret identical facts or simply disagree as to the factors appropriate to a determination of the risk that hostilities may resume.

For its part, the International Committee of the Red Cross (ICRC) has suggested that the test for determining when a NIAC has ended should focus on whether armed confrontations between the original parties to the armed conflict have lastingly ended in view of an analysis of conflict-specific factors, which may likewise promote uncertainty and prove unwieldy.

None of these tests has become widely accepted. None has been endorsed by a court. None of the existing theories provides sufficient guidance to safely and accurately pronounce the end of a NIAC. And, fundamentally, none adequately addresses the “messiness” of NIACs on its own. Nevertheless, they all contain substantial analytical factors that provide valuable guidance for constructing a practical test for determining whether and when NIACs terminate as a matter of law.

Uncertainty Embedded in the Existing Tests

In our article, we apply the competing tests for the termination of armed conflict to four case studies: the lengthy NIAC between Colombia and the Revolutionary Armed Forces (FARC); the Sri Lankan Civil War; the 2012 armed violence in Mali; and the armed conflict between the United States and al Qaeda. Doing so demonstrated widely divergent legal conclusions when the competing tests are applied to identical circumstances, leading to substantial legal uncertainty.

Applying the four competing tests to the U.S.-al Qaeda NIAC is instructive because each results in a different conclusion as to whether or when that armed conflict terminated. Although data concerning armed hostilities between the United States and al Qaeda is difficult to ascertain, the Reverse Tadić test seems to suggest an end to the NIAC no later than December 2016, when the United States no longer identified al Qaeda as one of the parties with which it was engaged in an armed conflict in Afghanistan in its semi-annual consolidated War Powers Resolution reports. Compare the 13 June 2016 letter from the President, which reads in relevant part “[t]he United States currently remains in an armed conflict against al-Qa’ida, the Taliban, and associated forces, and active hostilities against those groups remain ongoing” (emphasis added) with the 5 December 2016 letter from the President, which reads in relevant part “[t]he United States remains in an armed conflict, including against the Taliban, and active hostilities remain ongoing” (emphasis added).

By December 2016, publicly identifiable U.S. armed force directed at al Qaeda specifically had become sporadic and infrequent. According to the data available through the Uppsala Conflict Data Program (UCDP), there were just 29 events of armed conflict between the United States and al Qaeda in Afghanistan over the five years between 2012 and 2016, resulting in fewer than 80 deaths. This figure is down from 40 events resulting in 110 deaths in the previous five years, and 74 events resulting in 641 deaths between 2002 and 2006.

Then, according to data collected by the Armed Conflict Location & Event Data (ACLED) project and made publicly available (last accessed on Nov. 20, 2024), from January 2017 until the United States’ targeted killing of al Qaeda emir Ayman al Zawahiri in July 2022, the United States and al Qaeda engaged in no clashes. During the same period, al Qaeda and the Islamic Republic of Afghanistan engaged in just 26 clashes, resulting in a total of fewer than 100 deaths. UCDP data, for its part, reflects 32 hostile events between the United States and al Qaeda in Afghanistan between 2017 and 2022, resulting in 109 deaths. Together, this data suggests that hostilities between the United States and al Qaeda may have diminished below the Tadić threshold, terminating that NIAC even earlier than December 2016.

The No-More-Combat-Measures test would seem to indicate that the NIAC continues to this day, as the United States continues to employ combat personnel to detain alleged members of al Qaeda at the detention facility at Guantanamo Bay and episodically, if infrequently, employs armed violence against al Qaeda targets.

Applying the Peaceful Settlement test to the U.S.-al Qaeda NIAC illustrates the impossibility of the test’s application to some fact situations, as the United States and the leadership of al Qaeda are unlikely to enter negotiations or achieve a political resolution in the foreseeable future.

Finally, the No-Reasonable-Risk-of-Resumption test points to potentially irreconcilable conclusions. On one hand, if the public U.S. intelligence community assessments of al Qaeda are accurate, al Qaeda has suffered substantial losses and has long lacked the capability to attack the U.S. homeland or effect mass-casualty attacks. Nevertheless, those same assessments indicate that, even as the organization has “shifted away from centrally directed plotting,” al Qaeda maintains a desire to attack the United States.

Whether there is a reasonable risk that hostilities between the parties will resume presupposes the termination of hostilities in fact but leaves open whether they might reasonably be expected to resume given al Qaeda’s intent, its small but persistent presence in Afghanistan, and the absence of U.S. forces from that territory. This is a question on which outside analysts disagree. That liminal space makes the ongoing enmity between the United and al Qaeda a Schrödinger’s conflict, leaving uncertain whether IHL or human rights law is the appropriate legal framework and subject to retroactive resolution should al Qaeda suddenly launch a terrorist attack days, weeks, or even years from now.

The Farley-Pradhan Test

The three-part test we propose for determining the end of a NIAC incorporates factors from the existing tests and adds an all-important specific temporal factor. Borrowing from the Reverse Tadić test, the first part of our test examines whether organized hostilities have diminished below the intensity-and-organization threshold for triggering a NIAC under Tadić. Under the Tadić test for the existence of a NIAC, both its intensity and organization prongs must be satisfied for a NIAC to exist. Both our test and the Reverse Tadić test adopt a symmetrical requirement, meaning that should either prong of the Tadić test no longer be satisfied, a previously existing NIAC may no longer exist. But because insufficient organization or insufficiently intense armed violence may reflect only temporary conditions as a NIAC ebbs, the diminution of a situation of armed violence below the Tadić test’s floor is itself merely the threshold requirement of our test.

The second part of the Farley-Pradhan test envisions a thorough, fact-based analysis of the quality of a NIAC’s pacification. Factors to be evaluated in this part of our test include but are not limited to: whether the parties have fulfilled their initial objectives (or changed objectives); the statements of the parties regarding their intention to end the conflict; and the implementation of practical steps to end the conflict like the surrender of weapons, the exchange of prisoners, or the demobilization of fighters. At its core, the quality-of-pacification element of our test asks whether there are objective, observable indications that the parties to a NIAC intend to end that armed conflict.

The innovative third part of the Farley-Pradhan test is a five-month clock during which the first two parts are assessed. If, during that five-month period, hostilities have diminished below the Tadić threshold and objective factors indicate that the parties intend to terminate the NIAC, then the NIAC will have terminated as a matter of law. The five-month clock has its basis in ICC jurisprudence finding that a period of five months of armed violence is “to be regarded” as protracted for the purpose of establishing hostilities under Tadić. The use of the same period of time to assess whether a NIAC has ended once again seeks to impose symmetry between the onset and end of armed conflict.

This rigid requirement may have two results: to incentivize the parties to maintain peace (if a higher standard of law will be applied to their former opponents once the NIAC lapses); and to allow impacted civilians and observers to monitor and evaluate the component parts of the test and ensure that the proper applicable law is employed at all times, or to document continuing violations. It imposes certainty on the test’s application to situations of organized armed violence, while mitigating the revolving door conflict classification problem.

Returning to the U.S.-al Qaeda armed conflict, the Farley-Pradhan Test would result in a determination that hostilities between the two parties concluded no later than December 2016, excluding a separate analysis of hostilities between the United States and the expansive set of armed groups the United States’ labelled al Qaeda associates under the 2001 AUMF. It is also possible that the U.S.-al Qaeda NIAC concluded much earlier under our test. Unfortunately, it is difficult to reach a definitive conclusion as to the end of the U.S.-al Qaeda NIAC because of the dearth of publicly available data on U.S. combat operations targeting al Qaeda specifically.

The United States has not released data on its combat operations in Afghanistan that identifies the number of combat engagements in which it engaged against al Qaeda or its fighters. Nevertheless, the fact that the United States ceased to identify al Qaeda as one of the groups in which it was engaged in an active armed conflict in Afghanistan in its periodic War Powers Resolution reports by December 2016 suggests that, by that time, hostilities between the two parties had diminished below the Tadić intensity threshold, a suggestion corroborated by data collected and made publicly available by ACLED and UCDP. In addition to the likely diminution of intense armed violence between the parties, objective factors relating to the quality of pacification of the armed conflict point to its termination at least by that point: the United States announced a conclusion to its combat operations in Afghanistan in December 2014; by October 2015, fewer than 10,000 U.S. forces remained deployed in Afghanistan, down from a high of 100,000 in August 2010.

Finally, these factors did not change in the five months following December 2016. For example, in all of 2017, just fifteen U.S. servicemembers were killed in Afghanistan across all operations that year. And while ACLED data indicates no clashes between the United States and al Qaeda in all of 2017, UCDP data identifies just seven events in the first five months, resulting in 26 deaths. Under the Farley-Pradhan test, U.S. actions targeting al Qaeda from December 2016 on would have been governed by international human rights law, which would have imposed stricter legal requirements on the United States and afforded greater legal protections for individuals subsequently caught up in what the United States termed the “Global War on Terror.” It would also have entailed a much quicker resolution of U.S. detention operations at Guantanamo Bay with the exception of those individuals tried for violations of IHL.

Conclusion

We seek to nudge the debate over determination of the end of a NIAC toward legal certainty and operational practicality. We believe that a durational element is critical, although we recognize that the precise term may require further refinement. Indeed, there is ample room for further development and refinement of our effort on the basis of empirical work that combines both quantitative and qualitative analysis of NIACs from recent decades. In that context, our proposed test is a robust starting point to codify a binding standard that parties and courts can use to better apply IHL and regulate a return to legi generali.

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Benjamin R. Farley is the Director of the U.S. Department of State’s Office of Terrorist Detentions. The views expressed herein are solely those of the author and do not necessarily reflect those of the U.S. Government.

Alka Pradhan is a human rights attorney specializing in litigating the effects of torture on fair trials and an Adjunct Professor of Law at the University of Pennsylvania Carey Law School. The views expressed in this post are solely those of the authors and do not necessarily reflect those of the U.S. Government.

Photo credit: Marine Staff Sgt. Luis P. Valdespino Jr