The children (and wives) of foreign ISIS fighters: Which obligations upon the States of nationality? Francesca Capone* 1. Introduction The presence of Foreign Terrorist Fighters (FTFs) in Syria and Iraq triggers a number of questions that States, individually and collectively, do not seem equipped and/or willing to address. One of the most problematic aspects is represented by the claim, eloquently summarized in a famous tweet from President Trump, that there exists an obligation, incumbent upon FTFs’ States of nationality to repatriate them − and their family members − by proactively seeking their return also in the absence of formal mechanisms.1 Notably, after the military defeat of ISIS, the Syrian Democratic Forces (SDF) and the Iraqi Government are implementing different approaches to deal with foreign nationals accused of having ties with ISIS. On the one hand the SDF, ie a non-State armed group − opposed to the current Syrian Government − that is exercising governmental functions over part of the Syrian territory with the support of the Global Coalition against Daesh, has declared, on various occasions, that it is not willing nor able to prosecute FTFs and that it is equally not capable of managing the camps where FTFs’ family members are held.2 On the other hand, the Iraqi Government is relying on its sovereign right to prosecute adult FTFs, both men and women, but is asking States of origin to repatriate * Assistant Professor, Institute of Law, Politics and Development, Scuola Superiore Sant’Anna, Pisa. 1 F Capone, ‘Is Trump Right? Foreign Fighters and the States’ Obligation to Repatriate Them’ Versfassungsblog (10 March 2019) <verfassungsblog.de/is-trump-rightforeign-fighters-and-the-states-obligation-to-repatriate-them/>. 2 ‘SDF Calls for International Tribunal for ISIL Detainees’ (25 March 2019) Al Jazeera <www.aljazeera.com/news/2019/03/sdf-calls-international-tribunal-isil-detainees190325140845893.html>. QIL, Zoom-in 60 (2019) 69-97