The article tackles the problem of the proportionality of terrorism-based deprivation of citizenship under the ECHR. The author analyses ECtHR cases concerning deprivation of citizenship on such grounds, as well as other cases involving citizenship in various contexts. The approach of the Court to such cases embraces the analysis of arbitrariness and the consequences of denationalisation. Nevertheless, the article outlines that the exact content of these two fragments of the standard is rather obscure. Apart from Article 8 ECHR – being the most frequently used in citizenship litigation – Article 3 of Protocol No. 1 and Article 3 of Protocol No. 4 are also included in the analysis. This allows elaboration of the criteria that should be used for assessment of the proportionality of denationalisation. Finally, some remarks are made as to the legitimacy of denationalisation from the standpoint of the principle of proportionality intertwined with the irreversibility of such a sanction.

Emil Śliwiński, Proportionality of terrorism-based deprivation of citizenship under the ECHR, The International Journal of Human Rights, 2026.