Denationalisation of Foreign Terrorist Fighters

Dimitra Fragkou/ February 3, 2022/

Dimitra Fragkou[1]

Abstract: During the past years and specifically after the retreat of ISIS and Al-Qaeda forces in Syria and Iraq, thousands of European citizens who participated as Foreign Terrorist Fighters in those conflicts and their families are returning to their communities. States have sought to reduce the risk of expanding terrorist clusters on European soil through more restrictive legislation. The main impetus of the present post is the felt need to address the challenges posed by the recent expansion of denationalisation of European citizens accused οf terrorist acts abroad. For these reasons, the post reviews the UN Framework for denationalisation. It also reflects on how the recent developments in the European context may affect the future of human rights and international peace and stability. 

Keywords: Denationalisation, Foreign Terrorist Fighters, Counter-Terrorism, Statelessness 

Introduction: Setting the Framework – Ways of Citizenship Acquisition

Citizenship, as a principle, is obtained by birth, according to two distinct categories: a) jus sanguinis (or citizenship by descent), which can be traced historically to Roman law and has been traditionally incorporated in the civil law legal systems and b) jus soli (‘citizenship of birthright’) which is preferred by common law states. After birth, citizenship can also be obtained through naturalisation, whose provisions differ for each State. If no legal provision to the contrary exists, one person can hold more than one citizenship (dual citizenship).

Denationalisation of citizens can be voluntary or involuntary – the latter can occur on various grounds but must always be justifiable by falling into pre-determined legal categories. Such categories may be fraudulent acquisition, acquisition of other citizenship (for states who do not allow dual citizenship), residence abroad, service in a foreign army, and disloyalty/treason. Disloyalty or treason is provided for by the law of 14 Member States[2] and includes acts such as: committing serious crimes against the State, acting against national constitutional order and institutions, or acting against national interests. Certain countries limit the possibility of denationalisation due to disloyalty or treason only to naturalised citizens.

1. International Legal Obligations Against Statelessness – The 1954 and 1961 UN Conventions

In 1954 United Nations adopted the Convention Relating to the Status of Stateless Persons (hereafter ‘Statelessness Convention’)[3] and, in 1961, the Convention for the Reduction of Statelessness.[4]

The 1954 Convention, signed by 96 states as of January 2022, defines a stateless person as someone “not recognised as a national by any state under the operation of its law.[5] Further on, it safeguards a set of fundamental rights for the stateless, such as (but not limited to) the right to employment, education, and housing. 

The 1961 Convention aims to prevent statelessness and gradually reduce it. Therefore, the Convention focuses on an international framework that ensures every person’s right to a nationality. The Member States must establish safeguards in their nationality laws to prevent statelessness at birth and throughout all stages of life. 

The Convention, although explicitly prohibiting the deprivation of nationality which results in statelessness [Article 8(1)], allows the denationalisation of citizens who have been disloyal or otherwise conducted themselves in a manner “prejudicial to the vital interests of the State” [Article 8(3). his exception is exhaustive[6] and shall not be used by states to deprive someone of their nationality “on racial, ethnic, religious, or political grounds” [Article 9]. 

Articles 8(2) [failure to register, misrepresentation or fraud] and 8(3) [disloyalty] are exceptions to the general rule of Article 8(1) and, therefore, must be interpreted narrowly. Simultaneously, their scope of application has been further narrowed due to developments in international human rights law.[7]

Article 8(3), more specifically, permits involuntary denationalisation, when a citizen, (i) “in disregard of an express prohibition by the Contracting State rendered or continued to render services to, or received emoluments from, another State” or (ii) “conducted himself in a manner seriously prejudicial to the vital interests of the State.” Inconsistency to the duty of loyalty, when attributed to these acts, refers, according to UNHCR, specifically to the individual’s intent.[8]

For Article 8(3)(a)(i) and (ii) to be applied, a citizen must have acted inconsistently with their duty of loyalty to the Contracting State. The duty of loyalty is unequivocally an emotionally charged term. Τhe International Court of Justice (ICJ), when defining nationality in the Nottebohm Case, noted the social dimension of nationality as having a ‘genuine connection of existence, interests and sentiments, together with the existence of reciprocal rights and duties.’[9]

According to the interpretation of the terms of Article 8(3)(a)(i), services can be civil or military services, while emoluments can be of any kind, including “monetary rewards or other types of benefits.”[10]

Article 8(3)(a)(ii) requires an even higher threshold for denationalisation, requiring for seriously prejudicialconduct violating the vital interests of the State. Vital interests are of higher importance than national interests, the former being the State’s integrity, external security and constitutional foundations.[11] A direct causal nexus to the harmful outcome must exist for a conduct to be considered seriously prejudicial. Incidental harm does not suffice. Furthermore, deprivation of nationality is not applicable for acts that may occur in the future.  

2. Applicability of Articles 8(3)(a)(i) and (ii) to Foreign Terrorist Fighters

From the provisions analysed above, only the second, if domestic legislation also provides for it, may constitute a legal basis for the denationalisation of citizens engaged in terrorist conduct and -in terms of our discussion- FTFs.  

More specifically, subparagraph (i) explicitly mentions the offer of service to states, clarifying that it does not refer to services provided to or emoluments received from non-State entities, such as non-State armed groups -including terrorist organisations-, non-governmental organisations or businesses.

Subparagraph (ii), on the other hand, leaves interpretational space for terrorism-related denationalisation. Conduct falling under the terrorism umbrella, which is defined, inter alia, as aiming at “the destruction of human rights, fundamental freedoms and democracy, threatening the territorial integrity, security of States and destabilising legitimately constituted Governments”[12] can reasonably be interpreted as prejudicial to the vital interests of the State. 

UNHCR, in its Guidelines on Statelessness, urges states to stay abreast of developments in international law, especially human rights law and counter-terrorism policies, to amend possible violations of the provisions of Art.8(3)(a) of the 1961 Convention. What is particularly problematic in applying this clause is that there is no international consensus on the definition, interpretation and normative application of terrorism.[13] As such, the international counter-terrorism responses resort to a massive policy production, often vaguely formulated, which endangers the foreseeability of criminal law and may lead to denationalisation. This large body of international and regional legal instruments includes significant treaties, such as the 1997 Suppression of Terrorist Bombings Convention,[14] the 1999 Convention on Terrorist Financing,[15] and the 2005 Convention for the Suppression of Acts of Nuclear Terrorism.[16]

Great caution must be given to interpretations of membership to a terrorist group or an armed non-state actor. Being registered as a member or even having received training by a terrorist group should not suffice to deprive someone of their nationality. Similarly, it is significant for states to abide by the aut dedere aut judicare principle (prosecute or extradite) when serious indications for a terrorism conviction exist to prevent the spread of the phenomenon to other countries and inflict serious damage upon international peace and security.

3. State Practice concerning the Denationalisation of FTFs

It is estimated that approximately 5000 European nationals left Europe during the previous years to join ISIS and Al-Qaeda in the armed conflicts of Syria and Iraq.[17] Though foreign fighters are not a new phenomenon, the flows to the conflicts in Syria and Iraq were unprecedented in terms of numbers. Many of them have already returned, but a significant number remains abroad. These fighters were usually accompanied by family members, wives, and children, many of whom were born during the conflict.[18]

FTFs are viewed as posing a significant threat to their States upon return. Radicalisation Awareness Network (RAN), in its Manual on Responses to returnees: Foreign terrorist fighters and their families,[19] defines the threats in terms of gender and age. According to the Manual, men may have received combat skills and experience, may have been involved or witnessed atrocities, and may have had high ranks among the ISIS and Al-Qaeda operational structures. Women are understood as having the family supporting role and as mothers to future soldiers, having been indoctrinated on their significant role in building the ‘caliphate’ and potentially involved in the recruitment or indoctrination of children and others.[20] Children are considered as having received intense ideological indoctrination through education and socialisation. Children over the age of 9 are also portrayed as potential participants in hostilities or other conflict-related activities as child soldiers or auxiliary personnel and are expected to be severely traumatised. 

The majority of practitioners call for a scheme of initial repatriation (of those who have not yet returned) and further prosecution and rehabilitation of FTFs and their families, putting grave concern on their relationship with their communities and minimising their connection to terrorist networks. However, some states (Belgium, France, Germany, The Netherlands, United Kingdom) have chosen to denationalise and expel them or ban their repatriation.[21]

4. Possible Effects to the Human Rights of the Expatriated

Some authors point out that this practice is a typical example of the ongoing securitisation of European borders, following the tactics of expelling the ‘unwanted’ to foreign states.[22]  Denationalisation of FTFs has also been viewed as a modern form of exile.[23] While exile has been a form of punishment directly imposed by a state authority, modern banishment of terrorists (or alleged terrorists) comprises two different legal stages. Denationalisation first, and then expulsion or extradition, banishing the unwanted now alien. The latter stage may become complicated due to procedural safeguards against an arbitrary return for reasons, e.g., violation of the non-refoulement principle. Consequently, some states (such as UK and Belgium) prefer to strip convicted (or alleged) terrorists of their nationality when they are still abroad. 

In absentia[24] denationalisation poses significant threats to the human rights of the expatriated, possibly depriving them of the right to a fair trial and violating due process, or even making them susceptible to enforced disappearances, cruel, inhuman, or degrading treatment or even death penalty.[25] Since some of them may be in third countries during their denationalisation, they may stay in legal limbo, facing arbitrary and prolonged detention.

The expansion of denationalisation practices (instead of resorting to more suitable responses such as prosecution and rehabilitation) may severely undermine international counter-terrorism attempts. Banishing terrorists (or alleged terrorists) may very quickly send them off the radar, putting them under the direct influence of terrorist networks. Most significantly, this practice may severely undermine cooperation with other states, such as Turkey or Bangladesh, that have expressed their clear discontentment for operating as ‘hotels for foreign terrorists.’[26]


As we saw, Article 8(3)(ii) of the 1961 Convention on the Reduction of Statelessness may allow citizens’ legal involuntary denationalisation when convicted for terrorism. Nevertheless, the recent expansion of this clause is highly problematic. Its proponents argue that strengthening the very notion of citizenship is of absolute importance to connect it with a citizen’s positive obligations. This view draws back to classical notions of citizenship, according to which citizenship is either a privilege of allegiance to a feudal lord or a ‘social contract’. The other side argues that citizenship ‘is not a license that expires on misbehaviour’[27] primarily when modern penal systems evolved into rehabilitation and reintegration models. Indeed, States should be in a position to enforce alternative ways of justice instead of punitive denationalisation, which will safeguard both the human rights of the (alleged) terrorist and the rights for reparation of terrorist victims.

Finally, in strictly legal terms, Article 8(3)(ii) is an exception, and as an exception to a human rights clause must always be interpreted narrowly. The vagueness and the lack of international consensus of which acts constitute terrorism safeguard neither the rule of law nor the principle of foreseeability. As Members of an international community, States shall be very vigilant not to return to the dark ages of exile and banishment, the same way minorities and political opponents were exiled in the past.

[1] Dimitra is a PhD Candidate at NOVA School of Law. She was a lawyer at the Greek Council for Refugees since 2016 and a legal advisor at the International Organization for Migration. She was appointed as a national point for Victims of Torture in Northern Greece for IOM.

[2] 15 before the exit of the UK from the EU. See accordingly, European Parliament, Acquisition and Loss of Citizenship in the EU Member States; Key trends and Issues, Briefing, July 2018, p. 7. 

[3] UN General Assembly, Convention Relating to the Status of Stateless Persons, 28 September 1954, United Nations, Treaty Series, vol. 360, p. 117, available at: 3ae6b3840.html [accessed 1 February 2022]

[4] UN General Assembly, Convention on the Reduction of Statelessness, 30 August 1961, United Nations, Treaty Series, vol. 989, p. 175, available at: html [accessed 1 February 2022]

[5] Supra n.3, Article 1(1).

[6] UN High Commissioner for Refugees (UNHCR), Guidelines on Statelessness No. 5: Loss and Deprivation of Nationality under Articles 5-9 of the 1961 Convention on the Reduction of Statelessness, May 2020, HCR/GS/20/05, available at: [accessed 22 January 2022], para. 53.

[7] Supra n. 6, UNHCR, Guidelines on Statelessness No. 5, para. 48.

[8] Supra n.6, UNHCR, Guidelines, para. 57.

[9] Nottebohm Case, Liechtenstein vs Guatemala (Second Phase) [1955] ICJ Rep 4, 23. Also, Boll Alfred, “Nationality and Obligations of Loyalty”, available at: kIntLaw/2005/4.html

[10] UN Conference on the Elimination or Reduction of Future Statelessness, Summary Records, 20th meeting of the Committee of the Whole, 24 April 1961, A/C0NF.9/SR.20, p. 7.

[11] Supra n.6, UNHCR, Guidelines, para. 62.

[12] UNGA Res. 60/288, 20 September 2006, preambular para. 7.

[13] Samuel (2012) p.16.

[14] International Convention for the Suppression of Terrorist Bombings, 2149 UNTS 256, Article 2.

[15] International Convention for the Suppression of the Financing of Terrorism, 2178 UNTS 197, Article 2.

[16] International Convention for the Suppression of Acts of Nuclear Terrorism, 2445 UNTS 89, Article 2.

[17] McCaul and Thompson, (2015) 8.

[18] Maher, S., Neumann P. (2016).

[19] European Commission, Migration and Home Affairs, RAN Manual, July 2017, available at:

[20] Lakhani & Ahmadi (2016).

[21] See for a more thorough analysis, Laine T. (2017); Bolhuis and Van Wijk (2020)

[22] See, on this relation, the insightful analysis of Sandra Mantu (2018).

[23] Macklin, A. & Bauböck, R. (eds) (2015), pp. 1-2.

[24] In absentia: not being present to trial, here not being present to the territory of the state.

[25] See, e.g. the cases of the trials of alleged ISIS members in Iraq, Bolhuis and Van Wijk (2020), p. 362, note 98, citing UN Assistance Mission for Iraq (2020) Human Rights in the Administration of Justice in Iraq, Geneva: OHCHR, available at: 

[26] Ibid, p.9, note 100. 

[27] Macklin, supra n. 22 citing Patrick Weil (2013).

HOW TO CITE THIS BLOG POST: Fragkou, Dimitra. “Denationalisation of Foreign Terrorist Fighters”. NOVA Refugee Clinic Blog, January 2022, available at:

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About Dimitra Fragkou

Dimitra Fragkou is a PhD Candidate in NOVA School of Law. She has worked as a lawyer in the Greek Council for Refugees since 2016. She also been a Legal Counsellor for the International Organization for Migration (IOM), been appointed as a focal point for Victims of Torture in Northern Greece. She has served as a caseworker for the European Asylum Support Office (EASO) in the Aegean islands.