countermeasures

In international law, countermeasures are acts that would normally be unlawful but are rendered lawful because they are taken in response to a prior internationally wrongful act by another state, with the aim of inducing that state to comply with its obligations. They are a circumstance precluding wrongfulness under the law of state responsibility.

The authoritative framework is the International Law Commission's Articles on Responsibility of States for Internationally Wrongful Acts (ARSIWA, 2001), particularly Articles 22 and 49–54. Key requirements include:

• Prior wrongful act: there must be a breach attributable to the target state.
• Purpose: countermeasures must aim to induce compliance, not to punish.
• Proportionality (Art. 51): they must be commensurate with the injury suffered.
• Reversibility: as far as possible, they should permit resumption of the obligation.
• Prior call: the injured state should normally notify and offer to negotiate (Art. 52).
• Prohibited measures (Art. 50): no use of force, no violation of fundamental human rights, humanitarian obligations, or peremptory norms (jus cogens).

Countermeasures are distinct from retorsion (unfriendly but lawful acts, such as recalling an ambassador or imposing visa restrictions) and from sanctions authorised by the UN Security Council under Chapter VII. They are typically self-help measures taken by an injured state, though Article 54 leaves open the contested question of countermeasures by states other than the injured state in response to breaches of erga omnes obligations.

Leading judicial treatment includes the ICJ's Gabčíkovo–Nagymaros Project (Hungary/Slovakia, 1997), which set out conditions for lawful countermeasures, and the earlier Air Services Agreement arbitration (United States/France, 1978). In the WTO system, the term is used in a more specific sense under the DSU Article 22 for suspension of concessions authorised by the Dispute Settlement Body.