of terrorism upon their return.22 Experience has shown that threats and attacks also emerge frequently without any “foreign” engagement.23 The threat that returnees pose in countries of return or relocation is inherently difficult to quantify and requires ongoing analysis. The UN Security Council has noted that a key element of the risk arising from FTFs relates not only to their return but to their impact in the conflict zones themselves. UNSC resolutions on FTFs, and others focused on particular terrorist groups,24 explain the significance of the issue by referring to the impact of FTFs on “the intensity, duration and intractability of conflicts,” as well as the “serious threat to their States of origin, the States they transit and the States to which they travel, as well as States neighbouring zones of armed conflict in which foreign terrorist fighters are active and that are affected by serious security burdens”.25 Commentators also refer to the impact of FTFs on the sustainability and operations of organizations such as ISIL, which rely on a constant flow of recruits to sustain their ranks, not least due to very high casualty rates. Legal and policy responses directed at alleviating one area of risk (e.g., in states of origin) should be mindful of the potential to contribute to other risks (e.g., in conflict zones), as well as to the need to evaluate risk in the short and longer term. A broader risk analysis would also take into account threats associated with the increasing polarization of society to which FTFs, and state responses to them, may contribute.26 Crucial questions are who is going and coming back, where to and from and, in both cases, why? These are key questions that must inform policies. While studies thus far are limited in scope, a number of reports by civil society, academic and inter-state institutions, including the UN Office of Counter-Terrorism (UNOCT), contribute to our understanding of FTF motivations and contributing factors, including by giving voice to disengaged FTFs.27 22  See, for example; C. Lister, “Returning Foreign Fighters: Criminalization or Reintegration?”, the Brookings Institution, August 2015, p. 2, <www.brookings.edu/wp-content/uploads/2016/06/En-Fighters-Web.pdf>, which notes: “While genuine, the potential threat posed by returning FFs should not be overly exaggerated. Statistical analyses based on historical data – such as one by Hegghammer – have suggested that no more than 11 percent of FFs will pose a terrorist threat upon their return home”. 23  For example, see the statement by the EU Counter-Terrorism Coordinator in 2016 noting that it would be erroneous to focus on foreign threats when many attacks are from homegrown terrorism, in A. Reed, J. Pohl and M. Jegerings, “The Four Dimensions of the Foreign Fighter Threat: Making Sense of an Evolving Phenomenon”, International Centre for Counter-Terrorism, June 2017, p. 7, <www.icct.nl/publication/ the-four-dimensions-of-the-foreign-fighter-threat-making-sense-of-an-evolving-phenomenon>. 24  Related UNSC resolutions have specifically targeted groups such as ISIL, Al Nusrah Front, and entities associated with Al-Qaida, and referred to FTF obligations in this context. See, for example: UNSC Resolution 2249 (2015). 25  UNSC Resolution 2178 (2014), op. cit., note 1. 26  For one assessment of the “shifting threats” posed by foreign fighters see: A. Reed, J. Pohl and M. Jegerings, “The Four Dimensions of the Foreign Fighter Threat”, op. cit., note 23. The four main threats related to travel, return to their countries of residence, the threat posed by lone actors and sympathisers, and finally, the increasing polarization of society. 27  The UNOCT report goes to some lengths to explicitly acknowledge its limitations. See: “Enhancing the Understanding of the Foreign Terrorist Fighters Phenomenon in Syria”, UNOCT, July 2017, p. 52 (hereafter, UNOCT Report July 2017), <www.un.org/en/counterterrorism/assets/img/Report_Final_20170727.pdf>. Guidelines for Addressing the Threats and Challenges of “Foreign Terrorist Fighters” 13