Measures restrictive of rights which are adopted by states in response to conflicts or crises might be characterised as limitations to rights, as derogation measures, or as human rights violations. For those who are subject to rights-restrictive measures, the characterisation of such measures has significant consequences. If the measures are deemed (ultimately by a decision-making court or treaty body) to be limitations, they will be justified under the relevant human rights treaty, and states parties can adopt such measures lawfully, without more. However, if the measures amount, in substance, to derogation measures, certain additional conditions must be met if they are to be justified under the treaty. A question arises as to what those conditions for valid derogation are. [---]