Demands for the modification of the historic Indus Waters Treaty (IWT), by India, have been predicated on a number of untenable legal arguments. Amongst these is India’s incorrect reliance on the international law doctrine of fundamental change of circumstances, known by the Latin maxim of rebus sic stantibus (translated: “things thus standing”).
Where applicable, fundamental change of circumstances allows for the termination or suspension of a treaty if the circumstances under which the treaty parties operate have departed radically from those existing at the time of its conclusion. Rooted in customary international law, the doctrine is codified in Article 62 of the Vienna Convention on the Law of Treaties 1969 (VCLT). This provision must be read against the background of another Latin maxim, pacta sunt servanda (translated: “agreements must be kept”), which is enshrined in Article 26 of the VCLT.
What pacta sunt servanda establishes is that treaties are intended to be enduring documents that, as a general rule, cannot be avoided easily. As such, the mechanisms under the VCLT that allow a State to escape a treaty obligation are carefully policed. This is written in Article 62 of the VCLT and its account of fundamental change of circumstances. The provision establishes a series of prerequisites for its invocation, the cumulative effect of which is to make the doctrine very difficult to invoke. They are:
- The change must be fundamental and have occurred with regards to the circumstances existing at the time of the treaty’s conclusion.
- The change must not have been foreseen by the parties at the time the treaty was concluded.
- The existence of the circumstances must have constituted an essential basis of the consent of the parties to be bound by the treaty.
- The effect of the change must be to radically transform the extent of obligations still to be performed under the treaty.
As one commentator has noted, the cumulative effect of these criteria is such that the contemplated changes must individually or collectively:
“[D]estroy or […] modify totally the basis of the obligation based on the factual and decisive situation in existence at the time the treaty was concluded as well as to make the actual or future realization of the objectives and goals of the treaty or of the obligation impossible.”
Furthermore, the Second Report on the Law of Treaties by Sir Humphrey Waldock (the UN Special Rapporteur on the Law of Treaties), served as a key preparatory document for the International Law Commission’s (ILC) Draft Articles on the Law of Treaties, and later became the foundation for the VCLT. Among other topics, the report discussed the principle of pacta sunt servanda and its relationship with rebus sic stantibus. The report states that,
“There is a general consensus of opinion that the principle rebus is only relevant to the case of what are sometimes called perpetual treaties […] the principle has no raison d’etre in the case of other treaties […] If the treaty is not of this kind, either the question does not arise, for the treaty can be terminated by other means.”
Therefore, if parties have already included provisions on how a treaty can be terminated or suspended, then the applicability of rebus sic stantibus is limited. Article XII of the IWT clearly specifies that the Treaty can only be terminated through a duly ratified agreement concluded for that purpose. This weakens India’s argument of invoking the “fundamental change of circumstances” doctrine, as the Treaty itself provides a clear mechanism for its modification and termination.
Fundamental Change of Circumstance Clarified by the International Court of Justice
The leading international authority on the proper scope of “fundamental change of circumstances” remains the judgment of the International Court of Justice (ICJ) in the Gabčíkovo-Nagymaros case, a dispute between Hungary and Slovakia over a joint dam project, the facts of which were as follows.
Under the terms of a 1977 bilateral treaty, Hungary and Czechoslovakia aimed to construct a joint hydropower system on the Danube River, enhancing hydroelectricity production, navigation and flood protection. In 1989, Hungary purported to suspend and later to abandon its part of the project due to environmental concerns and political changes. In response, Czechoslovakia unilaterally implemented “Variant C”, a modified dam system, after Hungary abandoned the project in 1989. Following Czechoslovakia’s dissolution in 1993, Slovakia became the successor State to the treaty obligations, and continued Variant C post-independence, exacerbating tensions.
The dispute was brought before the ICJ, where Hungary argued that it was able to terminate a treaty on the basis of a “fundamental change of circumstances”, namely Czechoslovakia’s dissolution. However, the ICJ rejected this claim, emphasizing that state succession does not automatically void treaties unless explicitly renegotiated.
Hungary’s argument failed. In its judgment, the Court acknowledged Czechoslovakia’s breakup as a significant political change but ruled that it did not constitute a “fundamental change of circumstances” under international law as the treaty’s core purpose, joint environmental and economic management of the Danube, remained achievable. However, Slovakia’s actions in continuing Variant C were deemed unlawful, as its unilateral modifications violated the 1977 treaty’s requirement for mutual consent. The result was a shared liability. Ultimately, the ICJ ordered both countries to negotiate in good faith and establish a joint operational regime for the dam system, emphasizing the importance of environmental considerations in treaty implementation.
The ICJ’s ruling established that even significant and unforeseeable political shifts, such as the dissolution of Czechoslovakia, do not automatically justify treaty termination unless they fundamentally alter the treaty’s underlying conditions.
Lack of Modern Examples of a “Fundamental Change of Circumstances”
The doctrine of rebus sic stantibus has never successfully invalidated a treaty in modern international law. The application of this doctrine is strictly limited to ensure treaty stability. The ICJ and the ILC have consistently emphasized the importance of maintaining treaty obligations over unilateral withdrawal, as seen in the Gabčíkovo-Nagymaros case, where even significant geopolitical changes did not justify treaty termination.
In the context of the IWT, Indian academics and authors have attempted to identify historical examples of a successful invocation of “fundamental change of circumstances” to support India’s unprecedented decision to hold the IWT in purported “abeyance”. Each of them, once examined, does not assist India.
The first example being quoted is of the Baghdad Pact of 1955, in which Baghdad purported to withdraw from a security agreement in 1959 after the Iraqi royal family was overthrown by a nationalist coup. There is no indication that Iraq claimed this event as a “fundamental change of circumstances” that entitled it to exit the Pact, but even if it had, the Gabčíkovo-Nagymaros case establishes that under the current law, political changes (e.g. the dissolution of Czechoslovakia) cannot serve as a basis for rebus sic stantibus. This episode does not, therefore, assist India’s position.
The second example being quoted is that of the Treaty of Friendship and Cooperation signed between Egypt and the Soviet Union in 1971. In 1976, Egypt unilaterally abrogated the treaty. Again this is not an example of “fundamental change of circumstances”; rather, Egypt claimed to be able to exit the treaty primarily on the basis of repudiatory breach by the Soviet Union, a different basis for treaty termination in international law. Furthermore, the abrogation of the Treaty was not accepted and was denounced by the Soviet Union. Since the matter was never accepted, or otherwise submitted to adjudication before an international court or tribunal, the legal validity of Egypt’s unilateral withdrawal remains questionable. Moreover, this incident also predates the ICJ’s ruling in the Gabčíkovo-Nagymaros case. The only authoritative interpretation of the “fundamental change of circumstances” principle is the one provided by the ICJ in 1997.
India’s Inaccurate Claim of Fundamental Change of Circumstances
India has claimed that a fundamental change of circumstances has taken place, since 1960, that mandates a modification of the IWT. In a letter sent to Pakistan on 30 August 2024, India claimed that:
“Fundamental and unforeseen changes in circumstances have taken place since the Treaty was executed that require a re-assessment of obligations under various Articles of the Treaty read with its Annexures. These changes, inter-alia, include: (a) significantly altered population demographics coupled with the connected agricultural and other uses of waters; (b) the need to accelerate the development of clean energy to enable India to align with any commitment of capping carbon emissions’ (c) the significant alteration of the security-landscape, including through cross-border terrorism in Jammu & Kashmir, which has impeded the smooth operation of the Treaty as well as India’s full utilization of its rights under the Treaty.”
As is clear from a plain reading of the VCLT and the jurisprudence of the ICJ, the doctrine of fundamental change of circumstances can only be invoked when a change is fundamental, unforeseen and radically alters treaty obligations. None of the grounds for invoking “fundamental change of circumstances”, by India, have any merit.
Population growth in India was a predictable trend and entirely foreseeable at the time of signing of the IWT in 1960. This is evident from India’s early initiatives to manage population growth, such as the family planning program launched in 1952, following the 1951 census. This proactive measure indicates that policymakers were well aware of the growing population trends and their implications. Furthermore, the increase in agricultural demand was also a predictable factor, being directly linked to population growth.
Climate change, much like population growth, is a predictable trend and therefore does not meet the strict criteria laid out in Article 62 of the VCLT. The concept of climate change due to human activities was first proposed in the late 19th century, and by the 1950s, evidence of CO₂’s warming effect had become increasingly convincing. This period saw a growing recognition of human activities’ impact on climate. The fact that climate change was already being discussed and researched – decades before the IWT’s signing – indicates that it was not an unforeseen circumstance.
India’s claim that population growth or climate change constitute unforeseen circumstances is flawed, as these are long-term, predictable phenomena. Unlike the geopolitical upheaval in Eastern Europe, in the Gabčíkovo-Nagymaros case, environmental and demographic shifts can often be addressed through collaboration. Critically, the ICJ’s strict criteria for invoking rebus sic stantibus shows that India’s argument is unsubstantiated, as it does not meet the threshold of rendering treaty obligations objectively impossible to fulfill.
With regards to the Bharatiya Janata Party (BJP) and India’s evolving political orientation, the ILC has acknowledged that “a radical change of political alignment by the Government of a country [that] might make it unacceptable, from the point of view of both parties, to continue with the treaty” could attract Article 62. It should be noted that both treaty parties need to be in agreement on the impossibility of performance and it cannot be a unilateral decision. Furthermore, the ICJ has clarified that Article 62 can only be successfully invoked if the change was so closely linked to the treaty that it “radically transform[ed] the extent of obligations”. Furthermore, the mere change of government, that leaves the juridical personality of the State (in this case India) unaffected, does not constitute a fundamental change. Hence, unilaterally holding the IWT in “abeyance”, based on the BJP’s political agendas and alignment, cannot justify India’s actions.
Moreover, as already explained, there is no example of a State successfully invoking the fundamental change of circumstances doctrine to walk away from a binding international obligation. The examples being quoted in the Indian media are nothing more than isolated diplomatic incidents, which have no precedential value in the face of a judgement of the ICJ on the matter.
Accepting India’s argument based on “fundamental change of circumstances” would set a dangerous precedent for global water-sharing agreements, potentially destabilizing international relations and undermining the principle of pacta sunt servanda. It is time that the international community becomes involved because the weaponization of water by India threatens the peace and security of the entire South Asian region.