Based on a longitudinal study of how these deprivation powers evolved between 2000 and 2022, the report concludes that: There is a clear trend of increased prevalence and greater applicability of nationality deprivation based on broadly defined ‘disloyalty’ security concerns. 37 countries added new grounds for nationality deprivation that relate to national security or counter-terrorism – equating to 1 in 5 countries studied. Half of these did not have any such powers on the books in 2000. In half of the countries introducing new deprivation powers these are explicitly linked to terrorism – providing for the possibility of stripping a person of citizenship following conviction for a terrorist act that is sanctioned under the state’s criminal law or for nationality deprivation if a citizen joins a terrorist group even without a conviction. Europe is the epicentre of the expansion of securitybased deprivation powers (18 countries), followed by the MENA region (8 countries). There is mixed picture in Africa, Asia Pacific and the Americas – some states increased deprivation powers, while others limited them. 15 countries repealed or constrained existing powers over the same period – an important but smaller counter-trend as compared to the number that expanded their powers. In Canada, nationality deprivation grounds were repealed just three years after their introduction. Readily available information on the use, in practice, of security-based nationality deprivation across states reveals some interesting details about the implementation of these powers: Lack of reporting on data makes it hard to gauge how much the measure has actually been used. The few available statistics suggest that the numbers affected are low. Cases are in the tens, or less, with the exception of Bahrain (434 cases) and the UK (212 cases). Some states – such as in Central Asia – that introduced nationality deprivation to address the perceived threat of ‘foreign fighters’ returning from Syria and Iraq, do not appear to have used these powers, instead focusing on repatriation, rehabilitation and de-radicalisation. International law protects the right to a nationality, prescribes the avoidance of statelessness and prohibits arbitrary or discriminatory deprivation of nationality, significantly constraining the freedom of states to instrumentalise the loss of nationality. The report shows that when evolving state policy and practice is held up against these international norms – synthesised in the Principles on Deprivation of Nationality as a National Security Measure – a variety of problems arise, such as a high risk of violation of the principle of non-discrimination. A number of UN mandate holders and human rights treaty bodies have engaged with this issue, expressing concern about certain facets of the expansion of state powers and their application. However, there is significant room for improvement in the measure of attention devoted by human rights monitoring bodies to nationality deprivation, given the troubling global picture revealed in this report. This global study highlights major concerns that come with instrumentalising citizenship in the fight against terrorism. Doing Concrete, individual cases expose a variety of complex outcomes following nationality deprivation, including: expulsion back to the country of former nationality; limbo in the country of former nationality due to obstacles to deportation; and burdening a third country, such as Turkey, because there is nowhere to send the denationalised person to. Nationality deprivation is not an easy 'fix' to the complex challenge of combatting international terrorism. so a) undermines the security of the most fundamental legal status one can obtain – a nationality, which is also protected as a human right; b) is often implemented without sufficient procedural protections or safeguards against statelessness; c) in practice leads to arbitrariness, second-class citizenship and discrimination against minorities; d) threatens the international legal order and relations between states, by passing the problem of dealing with a possible security risk to another state instead of each state taking responsibility for its own citizens; e) risks normalising denationalisation as a legitimate power for states to hold over their citizens, with a knock-on impact for efforts internationally to protect right to nationality and prevent statelessness. In light of this and of security experts’ warnings that this measure is counterproductive to the fight against international terrorism, it is imperative to call a moratorium on the use of citizenship stripping as a national security measure and for states to urgently revisit whether it is appropriate to keep these powers on their books. 5