State responsibility and causation of terror: The case against Pakistan

Operation Sindoor, launched by India in May 2025 following the Pahalgam terror attack, represents a critical moment in the legal and diplomatic engagement with state-sponsored terrorism.

India’s targeted strikes on Lashkar-e-Taiba (LeT) infrastructure in Pakistan Occupied Kashmir (POK) were framed not merely as retaliatory or defensive actions, but as a form of legal protest against Pakistan's prolonged complicity in fostering terrorist groups.

This article focuses on the doctrine of state responsibility under international law, which provides a foundational framework for holding states accountable for harms committed through or enabled by non-state actors.

As Tal Becker notes in the introduction to his work Terrorism and the State: Rethinking the Rules of State Responsibility, “terrorists operate beneath the radar of the international system," often committing violence that is indistinguishable in impact from traditional inter-state aggression, but evading responsibility due to the non-state identity of the perpetrators.

States are afforded immense power and legitimacy in the international legal order, including the monopoly over lawful force. These privileges carry corresponding obligations: the duty to ensure that their territory is not used to inflict harm on other states. When states tolerate or facilitate terrorist operations, even through omission, they breach these obligations and undermine the collective framework of global security.

Pakistan’s conduct is emblematic of this breach. Reports confirm that senior ISIS leaders enjoy the protection and hospitality of Pakistan’s intelligence agencies, particularly the ISI. Some reports also highlight the presence of active terrorist infrastructure, including training camps and ideological nurseries in POK, which continue to operate under the State’s watch.

Despite international condemnation and prior commitments to dismantle such networks, Pakistan has consistently failed to neutralise these threats. Meanwhile, in its official response to the Pahalgam attack, Pakistan’s Defence Minister Khawaja Asif denied any involvement, dismissing the incident as a pretext to malign the country. Yet, these denials ring hollow in the face of mounting evidence, which has long documented Pakistan's strategic use of terror proxies as instruments of foreign policy.

We now turn to the more fundamental question of how international law determines a state's legal responsibility for the acts of non-state actors, especially when conventional attribution standards fall short, as developed by International Court of Justice through its judgments in Nicaragua 1986, Palestine Wall case 2004 and DRC v. Uganda. Central to this inquiry is the idea of "causation", a concept richly developed in municipal law but increasingly relevant to contemporary international legal doctrine.

Becker's compelling theory of causation in state responsibility, particularly for terrorism, advocates a shift away from rigid agency models (as in the Nicaragua case) to a more realistic and normatively grounded understanding of how states contribute to international harm.

This work explores the viability of causation-based frameworks, drawing upon private law analogies, the work of legal philosophers such as HLA Hart and Tony Honoré, and relevant arbitral jurisprudence, to argue that Pakistan's toleration and enabling of terror groups like Lashkar-e-Taiba render it legally accountable under international law.

Historically, causation has occupied a more prominent role in domestic legal systems than in international law. Municipal law relies extensively on causal analysis to determine liability in both criminal and civil contexts. However, as Hersch Lauterpacht emphasised in Private Law Sources and Analogies of International Law (1926), there is no barrier to drawing from these domestic principles to enrich international legal development.

Lauterpacht contended that private law analogies are not merely supplementary, but often foundational to the evolution of public international law, particularly where normative lacunae persist.

In legal theory, the attribution of responsibility for harm caused by another typically rests on two foundational principles. The first is agency, wherein a person (the principal) is held directly liable for the actions of their agent. This concept is commonly applied in domestic legal systems to areas such as contract performance, property transactions and employment law. Agency principles also extend into international law, where they help delineate state responsibility for actions carried out by private individuals acting on its behalf.

The second and often broader basis for attributing responsibility is the principle of causation. Under this framework, liability arises not through direct control or delegation, but because the harm is seen as a consequence, either wholly or in part, of the act or omission of an initial actor. Causation, therefore, emphasises the chain of events linking an actor’s conduct to the resulting harm, making it a critical tool in attributing responsibility where agency is not clearly established.

This approach is especially pertinent to the legal regulation of terrorism, where the strictures of attribution often fail to reflect operational realities. For example, the International Law Commission's Draft Articles require proof that the private individual or irregular group acted on the state's instructions, direction or control (Article 8).

However, such a standard excludes a wide range of complicit or causally enabling conduct, such as the toleration of terror infrastructure or repeated failure to prosecute known perpetrators. This principle is directly applicable to international terrorism.

Pakistan's long-standing harbouring of terrorist actors, repeated refusal to prosecute known figures and tacit encouragement of cross-border violence represent systemic conduct that significantly increases the probability of terror attacks against India.

The principle of causation as a basis for state responsibility, distinct from the narrow agency paradigm, finds support in numerous international case laws.

The Samoan Claims (1902) and Portuguese Colonies Case (1928) both endorsed the idea that a state’s wrongful act or omission could render it liable for harms committed by non-state actors if those harms were reasonably foreseeable consequences of the state’s conduct. For instance, in the Samoan Claims, the looting by natives during a bombardment was held to be proximately caused by British and French military actions. Similarly, the Portuguese Colonies case rejected the notion that intermediate acts broke the causal chain, arguing that foreseeable consequences of a state's initial wrongdoing could still ground responsibility.

The Corfu Channel case (1949) provides a landmark example of causal reasoning supplanting agency requirements. Though Albania’s direct role in mine-laying could not be proven, the International Court of Justice still held Albania responsible for the explosions based on its failure to prevent them, treating this omission as a cause-in-fact of the harm.

This reasoning has been echoed in later cases, including the Kahan Commission Report (1983), which held Israel indirectly responsible for the Sabra and Shatila massacre due to its failure to foresee and prevent the Phalangist militias’ actions. Likewise, the United Nations Compensation Commission (UNCC) extended Iraq’s responsibility for losses even when caused by third-party acts on the grounds that these harms flowed foreseeably from Iraq’s invasion of Kuwait. The Iran–US Claims Tribunal decisions, especially dissenting opinions in Short v. Iran and Queens Office Tower, further support causation as an alternative organising principle by emphasising the state’s failure to act as enabling private violence.

Collectively, these cases shift the focus from who committed the final act to what state conduct enabled or triggered the harm, thereby advancing a nuanced, causation-based model of state responsibility in international law.

Returning to the Pahalgam attack, a causation-based model exposes Pakistan's substantial role. Unlike isolated or spontaneous acts of violence, this attack occurred in the context of a long and well-documented pattern:

• Sustained support: Pakistan's ISI has provided training, arms and intelligence to LeT and continues to harbour ISIS affiliates.

• Legal immunity: Known figures such as Hafiz Saeed continue to operate freely under state protection.

• Infrastructural tolerance: Terrorist camps in Pakistan-occupied Kashmir remain functional, as detailed in both international media and think tank reports.

• Denial and deflection: Despite overwhelming evidence, Pakistan's government repeatedly denies responsibility and deflects blame, as illustrated in its first response to the Pahalgam attack.

Such conduct cannot be dismissed as passive or incidental. Under Hart and Honoré's framework, and echoed in historic arbitral logic, these are precisely the types of enabling conditions that create liability. They are not mere failures to prevent, but acts of structural toleration that materially increase the risk of terrorism.

Thus, even without proving "effective control," Pakistan can be held responsible on the basis of a robust causation doctrine that reflects both legal philosophy and judicial precedent.

Causation is not a foreign or alien concept to international law. As Lauterpacht anticipated, analogies from private law enrich the doctrinal fabric of international responsibility. The legal philosophies of Hart and Honoré, as well as a century of arbitral jurisprudence, provide a compelling foundation to hold states accountable not only for what they do but for what they enable.

In applying this framework to Pakistan, the case is clear. The State’s conduct constitutes a proximate and material cause of repeated cross-border terror attacks. As international law evolves to meet modern threats, causation must emerge not as a fallback, but as a central doctrine of accountability. This shift is not merely doctrinal; it is moral and pragmatic. Sovereignty without responsibility becomes impunity. Causation, as both a legal and ethical principle, restores balance in assigning liability in an increasingly multi-actor global landscape.

Shashank Maheshwari is an assistant professor at Jindal Global Law School.