retorsion

Retorsion is a concept in international law describing a unilateral act by a state in response to a wrongful act or injury caused by another state. Such measures are lawful and non-forcible; they express displeasure and aim to persuade the other state to modify its behavior without violating international obligations.

Retorsions are distinguished from reprisals or countermeasures. Reprisals involve acts that would themselves breach international law but are allowed only after a prior wrongful act, subject to proportionality and necessity constraints. Retorsions, by contrast, do not require a prior breach and are not themselves illegal expressions of policy, though they must remain within the state's rights and obligations under international law.

Common examples include expulsion of diplomats or recall of ambassadors, suspension or alteration of treaty relations or privileges, visa restrictions, and the withdrawal of certain economic or diplomatic privileges. Retorsions are typically reversible and designed to coerce reform while avoiding violence or legal violations.

Legal status is based on customary international law and, where applicable, treaty law. States may employ retorsions so long as the measures do not themselves violate other international obligations, human rights norms, or jus cogens prohibitions. The proportionality and temporary character of retorsions are often emphasized, and actions should aim at the offending state's policies rather than its people.

In practice, retorsion serves as a diplomatic tool to express objections and influence behavior without resorting to armed force or illegal acts. Related concepts include countermeasures and reprisals.