A (Twisted) Microcosm Imbued with Secrets?

Jean d’Aspremont’s recent mind-expanding book ‘The Epistemology of the Secret: International Law as Revelation’ argues that international law, like any serious epistemological project, proceeds on the assumption that the world is a continuous stream of hidden knowledge which the discipline is duty-bound to reveal – except that, in the very act of revealing, international law also creates the hidden knowledge it purports merely to uncover, unveiling some truths while suppressing others. International legal texts, on this account, are not neutral repositories awaiting discovery: the act of ‘revelation’ is itself an act of ‘ordering’ – of determining what can be said, thought, perceived and actioned through the discipline.

In state responsibility, the role of causation in determining the availability, form and extent of reparations for wrongful conduct is a strikingly apt illustration of this dynamic. The Articles on State Responsibility for Internationally Wrongful Acts (ARSIWA) present causation as though it were simply there, waiting to be applied – a settled criterion, cursorily stated in Arts. 31, 34 and 36 ARSIWA, that adjudicators need only ‘reveal’ in each case. Yet, as this blog post will show, the practice of international courts and tribunals suggests the opposite: in choosing between multiple tests of ‘but for’, ‘directness’, ‘proximity’ or ‘foreseeability’, international judicial bodies are not excavating a pre-existing legal fact so much as constructing – case by case, and often without acknowledging that they are doing so – the very causal reality they claim only to identify. The kaleidoscope image in the post’s title seeks to stress precisely that: not only does the picture shift depending on which international judicial body one asks, but each forum’s ‘revelation’ of the applicable causal standard is itself a creative act, quietly foreclosing other ways the causal link could have been drawn in the given context.

Applicability of ARSIWA – and its Reparation Rules – to Human Rights Violations

As well known, state responsibility extends to human rights violations. Although ARSIWA is formally ‘without prejudice to any right’ arising from the breach of obligations owed to individuals under international law (Art. 33(2)), international judicial practice strongly suggests that the obligation to make reparation – i.e. restitution, compensation and satisfaction (Arts. 34-37 ARSIWA) – governs human rights violations too, by force of the customary rule of full reparation. That premise traces back to the PCIJ’s iconic pronouncement in Factory at Chorzów, which was later codified in Art. 31 ARSIWA, and also confirmed by the ICJ as applying equally to injuries suffered by individuals.

When international courts and tribunals decide on reparations as a consequence of state responsibility, no reparation can be awarded without causation, i.e. without a link between the wrongful conduct and the injury occurred (Lanovoy, p. 2). Art. 31(1) ARSIWA is explicit: full reparation is due ‘for the injury caused by the internationally wrongful act’ – and the same causal language recurs in Arts. 34 and 36(1) ARSIWA. Causation between the breach of law and the harm (here: a human rights violation) is therefore the hinge on which the availability, form and extent of reparation turn. Causation’s function is, thus, protective. It wards off speculative claims from injured parties, while barring punitive damages against the wrongdoing State, a form of relief that remains impermissible in light of the practice of international (quasi) judicial bodies.

Unlawful Expulsion of Non-Nationals: A Valuable Setting for Testing Causation in Reparation

To examine how this causal inquiry actually operates in the context of reparation, this post uses a high-stakes subject-matter as a microcosm: the unlawful expulsion of non-nationals. Expulsion affects millions of people every year, and a wrongful expulsion can trigger drastic, sometimes irreversible, consequences for an individual’s life and family. Such a measure is squarely an internationally wrongful act within the meaning of Art. 2 ARSIWA, and it happens to be one of the most heavily litigated corners of international human rights law – having generated a dense, albeit scattered, body of case law from multiple universal and regional (quasi-)judicial bodies. Given the laconic nature of ARSIWA and its Commentaries on causation, this jurisprudence – as ‘subsidiary means for the determination of rules of [international] law’ under Art. 38(1)(d) of the ICJ Statute – constitutes a rich and helpful pool of legal arguments on the subject, and, on d’Aspremont’s reading, a valuable setting for observing the discipline’s revelatory posture at work.

Before causation in the specific reparation context can even be considered, wrongfulness must be established. Expulsion of a non-national typically becomes unlawful under international law in one of three ways: 1) it breaches a substantive human right, e.g. the prohibition of refoulement or collective expulsion, or the right to family life; 2) it fails to respect procedural safeguards, such as those in Art. 13 ICCPR or Art. 1 of Protocol No 7 to the ECHR; or 3) when it is enforced unlawfully – through excessive force, means of restraint, or otherwise abusive physical conduct during removal (for more, see Molnár).

Where any of these occurs, the coercive act of the host State’s immigration authorities not only triggers state responsibility but also activates the full panoply of reparation under ARSIWA and beyond. The ILC’s 2014 Draft Articles on the Expulsion of Aliens confirm that. Seen through a purely human rights lens, the UN Human Rights Committee’s General Comment No 31 (2004) states that reparation for ICCPR violations ‘can involve restitution, rehabilitation and measures of satisfaction’ as appropriate, while the 2005 UNGA Basic Principles and Guidelines on the Right to a Remedy and Reparation add rehabilitation and guarantees of non-repetition to the classic ARSIWA triad. That reparation is applicable in expulsion cases is clear. The practical difficulty lies elsewhere: in figuring out which injuries are close enough to the wrongful acts to actually be repaired.

The Elusive Concept of ‘Injury’ – and its Causal Tether

Art. 32 ARSIWA defines ‘injury’ expansively, as encompassing ‘any damage, whether material or moral’, caused by the wrongful conduct. In the wrongful expulsion cases, injury can flow either from the unlawful expulsion order itself, or from the substandard manner in which removal was carried out – and it can ripple outward into secondary harms: loss of employment, disrupted schooling for children, family separation, psychological trauma, etc.

But only injury that is caused by, and ascribable to, the wrongful act qualifies for reparation. Not every consequence flowing from it does (ARSIWA, Commentary to Art. 31, para 9). As international law draws a line between injury resulting from the breach and injury merely following it in time, the question is: what test to employ to draw that line?

The Plurality of Causation Tests: A Kaleidoscope, Not a Single Lens

Remarkably, causation – so central to the entire reparations edifice – remains comparatively under-theorised. And international judicial practice offers no single formula either. The common starting point is the ‘but for’ (conditio sine qua non) test: a factual causation mechanism asking whether the injury would have occurred absent the wrongful act. If it had happened regardless, no reparation is due. Yet, the ‘but for’ test, standing alone, is not sufficient in itself – it does not filter out injuries that are technically consequential but legally too remote.

To do that filtering, international adjudicators reach for supplementary tests: ‘directness’, ‘unbroken causal link’, ‘proximity’ and ‘foreseeability’. These borrow from the old Roman-law maxim injure causa proxima, non remota, inspicitur. Still, in judicial practice, almost every move is allowed on the dancefloor of causal inquiry, given that ‘[n]o specific test of causation is prescribed by international law’ (Guiding Principles on Shared Responsibility in International Law). Not only do the plethora of these tests in judicial pronouncements explain the situation that ‘causation’ and ‘remoteness’ resist generalisation (Wittich, para 17), but some substantive regimes even prescribe their own bespoke causation standards (see e.g. UN Security Council Resolution 687 (1991) on Gulf War reparations).

ARSIWA and its Commentaries treat the topic cursorily: symptomatic is the minimalistic wording in Arts. 31, 34 and 36, without elaboration. One explanation is that causation standards are inherently context-dependent and resist a one-size-fits-all formula (Wittich, para 17). But other scholars (e.g. Shelton, 846; Crawford, 492; and Lanovoy, 38) caution that this deceptively simple language masks a series of complex legal issues stemming from causation. Even the ILC itself essentially raised its hands and concluded in the Commentary to Art. 31 that the precise standard of causation must be determined on a case-by-case basis, in light of the relevant primary obligations (substantive rules).

Mapping International Judicial Practice: A Fertile but Fragmented Field

Given the ILC’s own indetermined position and the increasing caseload on expulsion-related matters before regional human rights courts (and also beyond), this jurisprudence offers a fertile ground to understand better how causal inquiry works in reparation cases. The following draws on rulings from judicial bodies as varied as the ICJ (most notably Diallo), the ECtHR, the IACtHR, the AfCtHPR, the Iran–US Claims Tribunal, the Eritrea–Ethiopia Claims Commission, and the UN Compensation Commission. Most recently, the CJEU has entered the fray with the Grand Chamber ruling in WS and Others v Frontex, offering fresh insights into how a supranational court approaches causation in expulsion-related cases (albeit with respect to the human rights responsibility of an organ of a (supranational) international organization, Frontex).

One important caveat: expulsion-related reparation claims pursued through diplomatic protection and inter-state mechanisms exhibit different procedural features and evidentiary requirements than those brought by individual petitions before regional human rights courts. Even so, the causation methodologies developed by the latter exercise a gravitational pull on other adjudicators, at least to some degree – making cross-fertilisation, however imperfect, a real phenomenon.

Discernible Trends and Blurred Lines

Surveying this scattered international jurisprudence reveals several distinct – and not entirely reconcilable – tendencies.

A recurrent feature is applying the ‘directness’ or ‘proximity’ standards in expulsion cases. The ICJ requires a ‘sufficiently direct and certain causal nexus’ (Diallo, para 14), whereas the ECtHR tends to apply a ‘proximity’ standard, setting a comparatively high threshold for awarding pecuniary damages for both material and non-material harm in expulsion cases (Pusztai, 148-152). At the same time, the African Court requires directness in relation to loss of income but accepts an indirect connection as sufficient for moral prejudice (Anudo).

The IACtHR, by contrast, adopts a markedly more lenient approach, often simply asserting that a causal link exists without ever articulating the standard it is applying – a methodological opacity that makes its jurisprudence hard to systematise or predict (Pusztai, 123, 152).

Unlike regional human rights courts, the Iran–US Claims Tribunal has historically shown less appetite for a relaxed ‘but for’ test, adhering instead to a stricter approach to the causal chain. On multiple causation more specifically, the Tribunal has rejected ‘parallel causation’ arguments. In the Yeager and Leach cases, the Tribunal denied compensation for lost income on the ground that the claimants’ employment would have been terminated by their employer regardless of the expulsion, severing the causal chain the claimants sought to establish.

The CJEU, interestingly, appears to be context-specifically relaxing the causation test for the EU’s non-contractual liability – which is ‘directness’ by default (Katsoni) – in those expulsion cases where vulnerable asylum seekers are involved and under specific circumstances, particularly in scenarios of overdetermined refoulement, such as in WS and Others (paras 154-161). It should be added that what was at stake here was not the responsibility of a State, but that of an international organization, namely the EU.

A further recurring pattern is that international judicial bodies, the ICJ included, frequently dispose of causation questions simply by finding that the expelled individual failed to prove causation, without ever clarifying what standard was applied or how it was applied to the facts. The ICJ’s insistence on the ‘directness’ test across very different areas of law stands in stark contrast with the ILC’s own (and several scholars’) preferred view that causation standards would be highly dependent on the primary rules breached and the type of injury suffered, rather than being imported wholesale from one area of law into another.

Also, a strict directness standard, applied indiscriminately, risks undercutting both the restorative function of state responsibility (by denying reparation for genuinely connected harms) and its deterrent function – without making it punitive – by reducing the practical cost of States’ engagement in unlawful expulsion practices. The ECtHR’s demanding proximity threshold is an illustrative example: such a standard may sit uneasily with the normative function of reparation ‘to wipe out all the consequences’, as far as possible, of the wrongful act (PCIJ, Factory at Chorzów, 47; ICJ, Diallo, para 24).

The Conundrum and a Proposed Way Through It

All this, however, reveals a deeper structural difficulty. Set the causation bar too high (directness, strict proximity), and responsibility is unlikely to result in full reparation – the wrongfully expelled individual is left under-compensated. Set the bar too low (as arguably the IACtHR’s practice risks doing), and reparation drifts toward something functionally indistinguishable from punitive damages – a result international law expressly disavows (see similarly, Lanovoy, 62).

A more conceptually defensible middle path, inspired by Pusztai, runs as follows: notwithstanding that the wrongful act may be a conditio sine qua non of a given harm, the State should bear no duty to repair that harm if it could not reasonably have been anticipated by the wrongdoer. That is a foreseeability standard, calibrated specifically to the purpose of the primary obligation breached (be it the prohibitions of refoulement, collective expulsion, or arbitrary pre-removal detention) and to the gravity of the particular factual circumstances constituting that breach.

Several reasons underpin adopting Pusztai’s refinements in expulsion cases. It is faithful to the ILC’s own choice that the primary norm should shape the applicable causation standard, rather than employing an across-the-board test. It allows foreseeability to be assessed in light of the specifics of each expulsion-related breach, while maintaining a coherent general framework that takes account of the concrete primary obligations involved. It also aligns with an objective regime of State responsibility, since what matters is not the mens rea of the State agents, but the objectively discernible purpose behind the primary obligation and the factual matrix of the breach (Pusztai, 163).

Final Thoughts – Looking Ahead

A more conceptually robust approach to causal inquiry in expulsion cases would help ensure that any reparation ordered is objective, principled and legally sound rather than seemingly arbitrary. It would enhance the predictability of outcomes and – perhaps most importantly for a field with already fragmented judicial practice – it would foster greater comparability of expulsion-related reparation decisions across adjudicative bodies confronting materially similar facts.

Circling back, finally, to d’Aspremont’s opening thoughts: perhaps the most candid lesson of this brief survey is that causation in reparation is not a secret waiting passively to be revealed by the right adjudicator or the right test. Rather, it is a standard that each judicial body actively constructs, and in doing so, oftentimes forecloses alternative approaches. Recognising causation as a matter of construction, rather than discovery, may be the first step toward building a more coherent framework that expulsion-related cases still lack. The ILC’s new focus area, ‘Compensation for the damage caused by internationally wrongful acts’, which addresses, inter alia, questions of causation, will most likely provide further impetus for academic reflection and doctrinal refinement in this field – and for courts to keep a close eye on these as well.

The views expressed in this blog post are solely those of the author and their content does not necessarily represent the views or the position of the European Union Agency for Fundamental Rights.