Yunusa Usman (Europa-Universität Viadrina) has posted A Normative Framing of the 'Foreign Fighter' in Contemporary Armed Conflicts (Global Journal of Politics and Law Research, Volume 12, No. 5, pp. 1-12) on SSRN. Here is the is the abstract:
With its unsettled conceptualisation, the notion of a foreign fighter has garnered renewed attention this Century due to the large numbers of non-nationals involved in hostilities in places such as Syria and Ukraine. Unsurprisingly, the use of foreign fighters has often drawn strong reactions from adversaries on the receiving end who often term them 'mercenaries' or 'foreign terrorists' and usually assert a right to subject captured foreign fighters to unilateral treatment standards. Some States of origin have also rushed to strip their nationals participating in armed conflicts abroad of their citizenship. In light of this tendency to resort to extra normative approaches, the Paper uses doctrinal research methods to explore the position of foreign fighters under international humanitarian law, as the lex specialis for armed conflicts and human rights law, as appropriate. It advocates that policymakers and legal commentators always view foreign fighters through the prism of relevant legal norms.