Despite her long story, that of the “foreign fighters” (FF) is a category which received, in the last years, growing interest from literature about their origins, characteristics and consequences of this phenomenon, particularly the terroristic dynamics of Jihadist origin. On the contrary of what is often believed, it is possible to observe examples of FF in the Panish civil war and in the Arab-Israeli conflict in 1948, showing a phenomenon which precedes and trascends the Islamic dimension . Between the most important players of the new renovated interest for the Foreign Fighters phenomenon there are surely governments' answers in the last decade, aimed to mitigate the risk that the fighters come back from conflicts' zones could become in turn responsable of terroristic attacks in their own State or of transferring their acquired knowledges. 
for the phenomenon of terrorism, also for the Foreign
fighters is not present an only and shared definition neither at an
academic level either at a governamental level. This absence makes
the identification and the answer to this phenomenon difficult at a
global and European level, due to the different interpretation of the
actions done by these players and what they represent for the
national security of the involved States. The absence of defined
criteria for the category of the Foreign Fighters makes the esteem
of their presence on the national and European land inaccurate.
Despite the difficulties of this operation, in 2016 the
Centre for Counter-Terrorism (ICCT) listed a
report on the phenomenon of the
Foreign Fighters inside the European Union. What arised from the job
was that in 2016 there were 3922 and 4294 FF on the European land, a
number estimated from an open-source informations and from answers
given by 9 member States to a questionnaire realized by the Dutch
research centre. The same report found out, in the Countries used as
study case, an absence of uniformity between the characteristics of
European FF, hightlighting the difficulty in the study of this
remains important the definition offered in 2014 by the 2178
Resolution of the UN Security Council, which describes the foreign
fighters as “«individuals who travel to a State other than their
States of residence or nationality for the purpose of the
perpetration, planning, or preparation of, or participation in
terrorist acts or the providing or receiving of terrorist training,
including in connection with armed conflict».”
gathered in the last months by the different reporter and experts
showed the presence of the foreign fighters in the fight in Ukraine
since the first phases of the invasion. By observing the recent
developments and the answers to the phenomenon by the foreign
fighters arriving in Kyiv, it was underlined a behaviour
diametrically opposite as compared to the one adapted by the European
States towards foreign fighters as regard the Islamic State (IS): it
seems in fact that in this case the European governments, echoing the
call to arms of president Zelensky,
not only accepted but also encouraged the presence of foreign
fighters on Ukraine territory. 
The most evident example- but not the only one- of the already said behaviour was observed by the English government in the words of the Foreign Affaris State and Commonwealth Secretary Liz Truss, who expressed support towards the English foreign fighters going toward Ukraine to fight the Russish troups .
Zelensky offered an esteem, whoce sources remain unknown, of the number of foreign fighters present on the Ukrainian territory as part of the "international legion" , which includes 16000 international fighters. It seems that the majority of the foreign fighters supporting Ukraine come from post-soviet States, such as Georgia and Belarus, but also testimonies of fighters from all over the world are recorded, between those: American, Indian, Italian and Japanese.
As underlined by the different analysts (Byman 2022; Marone 2022; Taneja 2022), the war in Ukraine may become theatre of a new approach towards the phenomenon of foreign fighters, a new behaviour that needs a careful observation to supervise how this foreing fighters, encouraged- for the first time- by their governments will be judged involved in motions of war crimes or contextually to their reintegration in their belonging society.
highlighted by Byman,
government should pay attention to the presence of ideologies of
extreme rights between the foreign fighters coming in Ukraine, seen
their documented growth in the Occident in the last years. 
The risk, in this case, is represented by the possibility that their presence during the conflict simplifies the creation of a more organized network and as a consequence more dangerous. This risk was highlighted also by Marone (2022), who defined the conflict as a new possible "gym of the transnational right's extremism".
So it is necessary to ask if this new behaviour means a new apporach to the foreign fighters' matter or if, as highlighted by the contrast with the modalities of answer to the same phenomenon in the previous years, is symptom of an Occidental double-standard, influenced maybe by the absence of the Islamic nature of the contemporary phenomenon and of its European localization.
Translated by Veronica Luzzi
 Kraehenmann S., (2014). “Foreign fighters under international law”, Geneva Academy of International Humanitarian Law and Human Rights, Academy Briefing No.7, p 5.
 Malet D. (2019). “Foreign fighters and terrorism”, p. 1.
 Ginkel V., Entenmann B. E., (2016). “The Foreign Fighters Phenomenon in the European Union. Profiles, Threats & Policies”, The International Centre for Counter-Terrorism – The Hague (ICCT), p.11.
 Risoluzione 2178/2014 del Consiglio di Sicurezza delle Nazioni Unite. Traduzione propria, testo originale: “«individuals who travel to a State other than their States of residence or nationality for the purpose of the perpetration, planning, or preparation of, or participation in, Il mondo dell’intelligence – www.sicurezzanazionale.gov.it 2 I foreign fighters: soggetti di diritto internazionale? terrorist acts or the providing or receiving of terrorist training, including in connection with armed conflict».” Disponible al: https://www.un.org/securitycouncil/s/res/2178-%282014%29
 Risale agli inizi dello scontro la chiamata del presidente Ucraino Zelensky ai cittadini del mondo per unirsi allo scontro contro l’invasione russa, definendoli come “cittadini de mondo, amici dell’Ucraina, dell’Europa, della pace e della democrazia”, come riportato dalla CNN in data 27 febbraio 2022. Disponibile al: https://edition.cnn.com/europe/live-news/ukraine-russia-news-02-27-22/h_9ffa23d19f5bde298a75a3e2be13e13d
 Taneja K., (2022). “The risks and dangers of foreign fighters taking up arms to fight Ukraine”.
 Sparrow A., (28 febbraio 2022). “Liz Truss criticised for backing Britons who wish to fight in Ukraine”, The Guardian.
 Termine utilizzato dallo stesso Zelensky per descrivere il gruppo formato da combattenti di diverse nazionalità arrivate a supporto dell’Ucraina.
 Bella T., Timsit A. (3 marzo 2022). “Zelensky says 16,000 foreigners have volunteered to fight for Ukraine against Russian invasion”, The Wasghington Post; e Marone F., (25 febbraio 2022), “I foreign fighters in Ucraina: il caso italiano”, ISPI.
 La crescente presenza di ideologie di estrema destra ha raggiunto il suo culmine - agli occhi del pubblico generale - nello scorso 6 gennaio 2021, con l’assalto a Capital Hill.