State of Necessity

State of necessity is one of six circumstances precluding wrongfulness codified in the International Law Commission's 2001 Articles on Responsibility of States for Internationally Wrongful Acts (ARSIWA), at Article 25. Unlike consent, self-defence, countermeasures, force majeure, and distress, necessity is invoked not against a wrongdoing state but as a unilateral plea that an act otherwise breaching an international obligation should not engage responsibility because it was the sole means of protecting an essential interest. The doctrine has deep customary roots — the Caroline incident of 1837 and the Russian Indemnity arbitration of 1912 are recurrently cited — but the ILC deliberately framed Article 25 in the negative ("Necessity may not be invoked... unless") to signal that it is an exceptional, narrowly bounded plea, not an open licence. The International Court of Justice confirmed in Gabčíkovo-Nagymaros Project (Hungary/Slovakia, 1997) that Article 25 reflects customary international law and that its conditions are cumulative.

The procedural and substantive mechanics are exacting. A state asserting necessity bears the burden of proof and must satisfy every condition in Article 25(1) and avoid the bars in Article 25(2). First, the act must be the only way to safeguard the interest — if any lawful alternative existed, however costly, the plea fails. Second, the interest protected must be essential: the ILC commentary admits this is assessed case by case, but examples include safeguarding the environment, ensuring the survival of the population, or maintaining essential services. Third, the peril must be grave and imminent, meaning objectively established and proximate, though the ICJ accepted in Gabčíkovo that a peril appearing in the long term may still be "imminent" if its realisation, however far off, is certain and inevitable. Fourth, the act must not seriously impair an essential interest of the state or states toward which the obligation exists, nor of the international community as a whole — a balancing test that weighs competing essential interests.

Article 25(2) imposes two absolute exclusions. Necessity may never be invoked if the international obligation in question itself excludes the possibility of invoking necessity — many treaties on the laws of armed conflict and humanitarian law contain such implicit or explicit exclusions. Nor may it be invoked if the state has contributed to the situation of necessity, a bar the ICJ applied decisively against Argentina-style arguments and against Hungary in Gabčíkovo, where the Court found Hungary had helped create the very conditions it later cited. Furthermore, Article 27 preserves the question of compensation for material loss caused by the act, so even a successful necessity plea does not automatically extinguish financial liability — it suspends wrongfulness, not the duty to make good the harm.

Contemporary practice clusters around economic crises and environmental emergencies. Argentina invoked state of necessity before ICSID tribunals to justify emergency measures during its 2001–2002 financial collapse, producing a fractured jurisprudence: the CMS v. Argentina award (2005) rejected the plea, the LG&E v. Argentina decision (2006) accepted it for a defined period, and the CMS annulment committee (2007) criticised the tribunal's conflation of Article 25 with the treaty's own non-precluded-measures clause. The ICJ in Wall Advisory Opinion (2004) rejected Israel's necessity argument for the barrier in occupied Palestinian territory, finding the route chosen was not the only means of protecting against the asserted peril. These cases show how rarely the plea succeeds before adjudicators.

State of necessity must be distinguished from adjacent pleas with which it is frequently confused. Distress (ARSIWA Article 24) concerns the immediate threat to the lives of persons in the author's charge, a narrower human-survival rationale, whereas necessity protects an interest of the state itself. Force majeure (Article 23) requires an irresistible force or unforeseen event rendering performance materially impossible and involuntary, while necessity involves a deliberate, calculated choice to breach. Self-defence (Article 21) responds to an armed attack and is governed by the UN Charter and ius ad bellum, not by the balancing of essential interests. Necessity is also distinct from military necessity, a permissive concept internal to international humanitarian law, and from the treaty-law doctrine of fundamental change of circumstances under VCLT Article 62, which terminates or suspends a treaty rather than excusing a discrete breach.

Edge cases and controversy persist. Scholars dispute whether necessity can ever justify the use of force, given Article 26's bar on derogating from peremptory norms (ius cogens); the prevailing view is that necessity cannot license violations of the prohibition on aggression. The COVID-19 pandemic and climate litigation have revived debate over whether public-health lockdowns affecting foreign investors, or emergency decarbonisation measures, might qualify, though no consolidated jurisprudence has emerged. Investment tribunals continue to grapple with the relationship between customary necessity and lex specialis treaty clauses, an unresolved tension flagged in the Argentine annulment decisions and revisited in subsequent BIT arbitrations.

For the working practitioner, state of necessity is a plea of last resort, to be advanced only when the documentary record can establish each cumulative element and exclude self-contribution. Government legal advisers drafting emergency decrees should anticipate the "only way" test by documenting the absence of lawful alternatives in real time, and should expect that even a successful plea leaves the state exposed to compensation under Article 27. Counsel before the ICJ, ITLOS, or investment tribunals should treat necessity as a high-risk argument with a poor track record, reserving it where treaty defences and other circumstances precluding wrongfulness are unavailable.