Clausula rebus sic stantibus

In public international law, clausula rebus sic stantibus (Latin for "things thus standing") is the legal doctrine allowing for treaties to become inapplicable because of a fundamental change of circumstances. It is essentially an "escape clause" that makes an exception to the general rule of pacta sunt servanda (promises must be kept).

Because the doctrine poses a risk to the security of treaties as its scope is relatively unconfined, it requires great care as to the conditions in which it may be invoked.

The doctrine is part of customary international law, but is also provided for in the 1969 Vienna Convention on the Law of Treaties under Article 62 (Fundamental Change of Circumstance), although the doctrine is never mentioned by name. Article 62 provides the only two justifications of the invocation of rebus sic stantibus: first, that the circumstances existing at the time of the conclusion of the treaty were indeed objectively essential to the obligations of treaty (sub-paragraph A) and the instance wherein the change of circumstances has had a radical effect on the obligations of the treaty (sub-paragraph B).

If the parties to a treaty had contemplated for the occurrence of the changed circumstance the doctrine does not apply and the provision remains in effect. Clausula rebus sic stantibus only relates to changed circumstances that were never contemplated by the parties. This principle is clarified in the Fisheries Jurisdiction Case (United Kingdom v. Iceland, 1973).

Although it is clear that a fundamental change of circumstances might justify terminating or modifying a treaty, unilateral denunciation of a treaty is prohibited; a party does not have the right to denounce a treaty unilaterally. (Though this has been debated.)

A key figure in the formulation of clausula rebus sic stantibus was the Italian jurist Scipione Gentili (1563 – 1616), who is generally credited for coining the maxim 'omnis conventio intelligitur rebus sic stantibus'. The Swiss legal expert Emer de Vattel (1714 – 67) was the next key contributor. Vattel promoted the view that 'every body bound himself for the future only on the stipulation of the presence of the actual conditions'; thus 'with a change of the condition also the relations originating from the situation would undergo a change'. While during the nineteenth century, civil law came to reject the doctrine of clausula rebus sic standibus, Vettel's thinking continued to influence international law, not least because it helped reconcile 'the antagonsm between the static nature of the law and the dynamism of international life'. While individual cases invoking the doctrine were much disputed, the doctrine itself was little questioned. Its provision in the 1969 Vienna Convention on the Law of Treaties established the doctrine firmly (but not without dispute) as 'a norm of international law'.

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