Hanne Cuyckens
Contemporary foreign fighters (FFs) often join so-called dual-nature groups, i.e. groups that can at the same time be qualified as a non-State armed group involved in a non-international armed conflict and a terrorist organization. Both international humanitarian law and counterterrorism (CT) legislation may hence be of relevance when assessing the legality of FF conduct. The CT perspective tends to remain predominant, however. This paper argues that, especially in terms of prosecution, due regard must be paid to both legal frameworks where possible. It also argues that national prosecution in the country of origin seems to offer the best prospects for realizing such cumulative prosecution.

Introduction: The multidimensional nature of the foreign fighter phenomenon

In 2014, an estimated 12,000 people from more than 80 countries had travelled to Syria in order to join groups, such as Jabhat Al-Nusra and Islamic State of Iraq and Syria (ISIS), and engaged in the civil conflict there.1 At the height of the conflict, in 2015, that number is thought to have gone up to almost 30,000 from more than 100 countries.2 The total number of men, women and children that have travelled from Western Europe to Syria and Iraq has been estimated at around 5000.3 Around 30 percent of the European foreign fighters (FFs) are believed to have returned to their home country in the meantime.4 Since the defeat of Islamic State (IS), those who have not returned are either believed to be dead or imprisoned in Syria or Iraq.5 The latter are still considered an important security threat and States seem to be doing everything possible to prevent these so-called FFs as well as their families from returning to their country of origin.6 Aside from the question whether such a position is actually the most efficient in terms of national security,7 the consequence of such an approach is that many of these FFs, especially in the camps in Syria, are just left there and no action is taken in their regard.8 It is the position of the present author, however, that it is of utmost importance for these FFs to be brought to justice, preferably in their State of origin.9 The question of the prosecution of (returning) FFs is, however, not an easy one. One of the main complicating factors in this regard is to be found in the difficult relationship between international humanitarian law (IHL) and counterterrorism (CT).

There is no uniform definition of FFs under international law. For the purpose of this paper, the following definition, as suggested by Sandra Krähenmann, will be used, namely that FFs are “individual[s] who [leave] [their] country of origin or habitual residence to join a non-state armed group in an armed conflict abroad and who [are] primarily motivated by ideology, religion, and/or kinship”.10 This definition is chosen here given that it, in the present author's opinion, reflects the current reality of the FF phenomenon in the most adequate manner.

If FFs are considered to be basically individuals joining a non-State armed group (NSAG) in an armed conflict abroad, it is by definition important to also assess their conduct from an IHL perspective. IHL applicability is especially straightforward for those having a continuous combatant function within the NSAG, i.e. concerning individuals “recruited, trained and equipped by such a group to continuously and directly participate in hostilities on its behalf”.11 It is slightly more complicated for those merely associated with the armed group, without having a combatant function. In order to assess whether their conduct could potentially be assessed under IHL, more specifically in terms of criminal accountability, a nexus with the armed conflict needs to be proven (see below).

Even if there is increasing consideration for the relevance of IHL in relation to the FF phenomenon, FFs are still mainly being assessed from a CT perspective. The term “Foreign Terrorist Fighter” used by the United Nations (UN) and the European Union (EU) in their policy documents on the matter represents a clear illustration of the underlying CT focus.12 As Krähenmann argues, the use of the term “foreign terrorist fighters” in UN Security Council (UNSC) Resolution 2178 (2014) definitely “blurs the lines [between CT and IHL] rhetorically”.13 The EU is not doing a much better job, as it appears “to use the terms FF, foreign terrorist fighters (FTF), and terrorists almost inter-changeably”.14 As was clearly highlighted by the International Committee of the Red Cross (ICRC) on more than one occasion, this robust CT discourse has significantly contributed to blurring the lines between armed conflict and terrorism and may potentially have important adverse effects on IHL.15

In this paper, a brief overview of the difficult relationship between IHL and CT will first be provided as well as its impact on the qualification of the activities of the FFs. Then, the question of prosecution of the (returning) FFs, central to this analysis, will be assessed. The assessment of the question of prosecution will start with a brief note on the opportunities for international prosecution as well as the avenues for domestic prosecution in the region, i.e. in Syria and Iraq. The further focus of the second section will be on prosecution by States of origin, and more particularly in an EU context. This focus is justified on the basis of two main grounds. First, the EU presents an interesting context because it allows for comparison between different States within a system which is striving towards more harmonization when it comes to criminalization more in general, but also with regard to the criminalization of FFs more in particular.16 Second, this is also the context the present author is most aware of, given that this has been at the centre of her previous research.17 Ultimately, it will be concluded that effectively prosecuting the FFs for the wrongful acts they may have committed is of utmost importance and that, when doing so, due regard must be paid to all relevant legal frameworks.[1]
Click to read Foreign fighters and the tension between counterterrorism and international humanitarian law: A case for cumulative prosecution