Exporting the Margin of Appreciation: the Role of the European Court of Human Rights in Shaping a General Principle on the Exercise of the International Judicial Function

It was in 1976 when, in the case of Handyside v. the United Kingdom, the European Court of Human Rights held that the European Convention on Human Rights “leaves to the Contracting States a margin of appreciation”. Forty-five years later, in 2021, Protocol No. 15 entered into force and incorporated the “margin of appreciation” into the Preamble of the ECHR. For a long time, the doctrine has been considered a unique feature of the European human rights system, consistently ignored or explicitly rejected by other international adjudicators. This article aims to assess whether the recent international judicial practice still confirms such a conclusion, or whether the margin has migrated across the case law of different international courts and is, nowadays, a doctrine that can be applied to the assessment of the scope and content of international obligations and to the review of compliance with such obligations in general.