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Islamic State of Iraq and Syria propaganda photo showing ISIS militants parading, 30 June 2014, in Raqqa, Syria.

Legal Implications of Canadian Foreign Fighters

by Michael Wickson

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The rise of the Islamic State of Iraq and Syria (ISIS) in 2014 captured international attention as the group captured much of Iraq and Syria, committing horrible atrocities in the process.1 Many individuals ventured to join their cause, including many Canadians.2 Many westerners also joined militant groups as foreign fighters to oppose the rise of ISIS in the Middle East, including a number of Canadians.3

In 2016, Dillon Hillier chronicled his adventure fighting ISIS in Kurdistan in a book entitled One Soldier: A Canadian Soldier’s Fight against the Islamic State.4 Hillier travelled to Kurdistan from November 2014 to January 2015 and joined the Iraqi Kurdish armed forces, the “Peshmerga,” as a foreign fighter. Four criteria define a foreign fighter:5 i) joining a militant group; ii) lacking citizenship or kinship with the parties; iii) lacking affiliation with an official military organization; and iv) being unpaid.6

Rainer Lesniewski/Alamy Stock Vector/HDG0DW

Map of the region, including Kurdistan.

Click to enlarge image

Kurdistan is a region that encompasses the areas occupied by ethnic Kurds and covers approximately 230,000 square miles.7 It sits at the confluences of Iraq, Iran, Syria, and Turkey.8 Despite lacking recognition as a state, the formal structure of Kurdistan could impact the status of the Kurdish militant groups, such as the Peshmerga and the Kurdistan Workers’ Party (PKK).

Hillier chose to travel to Kurdistan because the Peshmerga were the only force capable of stopping ISIS.9 The Peshmerga are the official armed force of the Kurdistan Regional Government under the Minister of Peshmerga Affairs.10 During his time there, he also fought alongside the PKK, a communist militant group that has been engaged in conflict with Turkey for several decades. The official nature of the Peshmerga contrasts sharply with the PKK. The PKK was formed in 1974 to establish a communist Kurdish state in southeastern Turkey.11 Inspired by Lenin, the PKK operated in a military fashion by conducting insurgent attacks within Turkey and violently eliminating Kurdish rivals.12 The PKK waged a campaign of terrorism against Turkey which lasted throughout the 1990s, killing thousands of Turks.13 As a result, the Canadian government placed the PKK on the list of terrorist groups.14 However, with the emergence of ISIS, the PKK cooperated with the Peshmerga to combat a common enemy.

Shortly after arriving in Kurdistan, Hillier grew impatient with the Peshmerga and found his way to the PKK in order to engage in combat. Unfortunately, by joining a listed terrorist entity, Hillier could be vulnerable to potential criminal jeopardy.

ZUMA Press, Inc./Alamy Stock Photo/GJ4BGR

A Peshmerga soldier at the frontline.

The Law

A general principle of international law is that a state’s domestic legislation cannot be applied outside of that state’s jurisdiction, which is formalized in section 6(2) of the Criminal Code whereby, “no person shall be convicted … of an offence committed outside of Canada.”15

However, there are exceptions, including legislative exceptions and the nationality of the individual.

Extraterritorial exceptions permit a state to legislate regarding the conduct of its citizens while abroad, but must await that citizen’s return before enforcement.16 Canadian foreign fighters could be held criminally liable upon returning to Canada for actions taken while participating in a foreign conflict. The nationality principle could make Hillier criminally liable under Canadian law, due to his Canadian citizenship. There are also crimes that any state has the jurisdiction to prosecute regardless of where the offence occurred. These crimes are considered violations against all humanity, including torture, war crimes, crimes against humanity, and genocide.17 In addition, there are pieces of Canadian legislation applicable to Canadian foreign fighters, specifically the Foreign Enlistment Act (FEA), and the treason and terrorism offences found in the Criminal Code.

Mackenzie-Papineau Battalion/Library and Archives Canada/e002712800

Members of the Canadian Mackenzie-Papineau Battalion in the Spanish Civil War, 1936–1939.

The FEA was introduced in the 1937 in response to approximately 1600 Canadians volunteering to fight in the Spanish Civil War.18 The FEA makes it an offense to join, “…the armed forces of any foreign state at war with any friendly foreign state,”19 as well as other offences, such as leaving Canada with the intention to enlist, and recruiting others to enlist. However, the FEA requires a “state at war,”20 a concept which is not particularly applicable to conflicts involving non-state actors. Also, the FEA does not include non-state actors in its definition of armed forces.21 Thus, joining groups such as the Peshmerga, the PKK, or even ISIS, would not violate the FEA.

The Criminal Code contains a few offences that could be applicable to foreign fighters. The first of these is high treason. High treason includes several sub-categories, including killing or threatening the life of Her Majesty, levying war against Canada, and assisting an enemy at war with Canada.22 In contrast to high treason, treason focusses upon violent attempts to overthrow the federal or a provincial government, providing information to an enemy state, or conspiring to commit high treason or treason.23 The third provision of high treason is most applicable to foreign fighters:

Every one commits high treason who, in Canada …assists an enemy at war with Canada, or any armed forces against whom Canadian Forces are engaged in hostilities, whether or not a state of war exists between Canada and the country whose forces they are.24

High treason applies to everyone while in Canada, but Canadian citizens can be charged regardless of the location of the treasonous actions. Therefore, high treason includes any action taken within Canada, but is limited to Canadian citizens if the treasonous actions occur abroad.

High treason also requires the Canadian to assist an armed force with whom Canada is engaging in hostilities. A foreign fighter could be guilty of a very serious offence regardless of their legal status within the conflict. A Canadian could be a fully lawful combatant in an armed conflict, but vulnerable to criminal sanction in Canada if they were affiliated with an enemy of Canada. Although Hillier was affiliated with a listed terrorist organization, the PKK, he was not engaged in hostilities against the Canadian Armed Forces, and therefore, would not be liable for high treason.

In the wake of 9/11, many terrorism offences were added to the Criminal Code., terrorism offences including financing, facilitating, and harbouring.25 There are some sections of the Criminal Code that are particularly applicable to foreign fighters, specifically, participating in a terrorist group, and the armed conflict exception.

A terrorist group is defined in two ways, either as having the purpose or intent to carry out terrorist actions, or to be a listed terrorist group.26 Public Safety Canada maintains a list of groups suspected of terrorist activities, which includes the PKK. It is an offence to participate in the activity of a terrorist group. Section 83.18(1) reads:

Every one who knowingly participates in or contributes to, directly or indirectly, any activity of a terrorist group for the purposes of enhancing the ability of any terrorist group to facilitate or carry out a terrorist activity is guilty of an indictable offence …27

This section has two elements to consider in the case of Hillier. The first element is knowing participation in any activity of a terrorist group. Foreign fighters provide a direct contribution to the group during an armed conflict. While Hillier was fighting with the PKK, he was fighting closely with other soldiers, and the group benefited from his presence. The second element is the purpose of facilitating or carrying out terrorist activity. Section 83.01(1) contains a lengthy list of terrorist activities, and it would only be an offence if the foreign fighter helped carry out one of these activities.28 Engaging in combat is not a terrorist offence according to this section. Hillier may have fought with the PKK against ISIS, but he did not contribute to any terrorist activities. Despite being a listed terrorist entity, the PKK was operating as an armed group to oppose ISIS when Hillier was associated with them. As such, he would not be liable under that section of the Criminal Code.

Associated Press/Hussein Malla/182472776500

Kurdish Peshmerga fighters are recruiting Westerners, including Canadian veterans, to fight with them against ISIS.

Section 83.01 of the Criminal Code also includes an armed conflict exception that would be useful to exclude him from criminal liability. According to the Criminal Code, a terrorist activity:

… does not include an act or omission that is committed during an armed conflict … in accordance with customary international law or conventional international law applicable to the conflict … to the extent that those activities are governed by other rules of international law.29

If Canadian foreign fighters joined an armed group that complied with international law to participate in an armed conflict, they would not be liable for terrorism offences under the Criminal Code. Lacking a definition of armed conflict in both the Criminal Code and the Interpretation Act,30 it is necessary to look at international law to define an armed conflict and to determine whether Hillier complied with the rules of international law.

To determine if an armed conflict truly exists, a test was developed by the International Criminal Tribunal for the Former Yugoslavia (ICTY). In Prosecutor v Tadic the ICTY held that:

an armed conflict exists whenever there is resort to armed force between States or protracted armed violence between governmental authorities and organized armed groups or between such groups within a State.31

This decision established a two-part test for the existence of an armed conflict by assessing the intensity of the fighting and the organization of the belligerent groups involved.32 Tadic demonstrated that only the organizational level of the armed group was a necessary factor, and state affiliation was not required. In Tadic, the ICTY determined that, “…[the] protracted, large-scale violence” that occurred in 1991–1992 between the numerous organized armed groups met the definition of an armed conflict.33

The conflict between Kurdish militant groups and ISIS was an armed conflict. In his book, Hillier described several combat situations, most notably a battle at a village called Tal al-Ward.34 The intensity of the battle likely matched the level of fighting in the former Yugoslavia in the early-1990s. He described a few other skirmishes in which he participated, suggesting protracted, large-scale violence. The Peshmerga and the PKK were both involved in the battle of Tal al-Ward against ISIS. Therefore, the level of organization of the Peshmerga, PKK, and ISIS, plus the prolonged nature of the violence, suggests an armed conflict did exist. Next, it will be necessary to determine if Hillier had the requisite status to lawfully participate in the armed conflict.

The status of persons in an armed conflict has been historically defined by the Geneva and Hague Conventions, and was revised by the Additional Protocols in 1977. Under international law, there are only two categories of people on a battlefield: combatants and civilians.35 Combatants can lawfully participate in an armed conflict, whereas civilians cannot, and they are subject to criminal liability if they do participate. In exchange, civilians receive greater protection under international law and cannot be targeted by military forces. In fact, everyone on a battlefield is a civilian unless they meet certain criteria to become a combatant. Foreign fighters would be no exception, and would need to qualify as combatants to avoid criminal liability.

Article 4 of the Third Geneva Convention of 1949 defines lawful combatants as:
Members of other militias and members of other volunteer corps, including those of organized resistance movements, belonging to a Party to the conflict and operating in or outside their own territory.36

Kurdishstruggle/Alamy Stock Photo/FT5BGX

Women fighters with the Kurdish PKK guerrillas with rocket propelled grenades and a heavy machine gun shown in a propaganda photo released by the PPK, 8 August 2014, in Iraqi Kurdistan.

Members of the Peshmerga and the PKK could fall into this class. However, there are additional conditions that must be met. Specifically: they must be commanded by a person of responsibility; they must be recognizable at a distance by a fixed distinct emblem; they must overtly carry weapons; and they must comply with the laws and customs of war when conducting military operations.37 These conditions restricted combatant status to those who waged warfare in the traditional sense.

The Additional Protocols significantly broadened the definition of a lawful combatant:
The armed forces of a Party to a conflict consist of all organized armed forces, groups and units which are under a command responsible to that Party for the conduct or its subordinates, even if that Party is represented by a government or an authority not recognized by an adverse Party. Such armed forces shall be subject to an internal disciplinary system which, inter alia, shall enforce compliance with the rules of international law applicable in armed conflict.38

This modernized definition of combatant achieved two things. First, it removed the requirement for uniforms and for openly carrying weapons. Secondly, it reinforced the most important aspect of qualifying for combatant status: “compliance with the rules of international law.”39 This definition makes anyone into a combatant if they are part of an organized group fighting in an armed conflict, as long as they comply with international law. Thus, members of the Peshmerga would likely be combatants, and the members of the PKK could be combatants if they demonstrate compliance with the second condition. The requirement to comply with international law would preclude any Canadian who joined ISIS from using the armed conflict exemption under the Criminal Code, regardless of their individual acts. They would not be lawful combatants because ISIS, as an armed group, failed to comply with international law, and so they would not be lawful participants in the conflict.

Hillier would be a combatant in an armed conflict and immune from criminal liability as long he did not participate in any crimes barred by international law, such as war crimes, crimes against humanity, or genocide.40 Unfortunately, at one point in the book, Hillier described the “worst day of his life” when he witnessed a war crime. He was with a group of PKK soldiers following the battle at Tal al-Ward. The group encountered an unarmed villager, who the PKK soldiers shot in the street.41 There is no indication that the act was “widespread or systematic,” and so it would be a war crime rather than a crime against humanity, specifically a willful killing under section 8(2)(a)(1) of the Rome Statute.42

Witnessing this war crime placed Hillier in an awkward position for two reasons. First, he could be considered a party to the act of the PKK soldiers and subject to prosecution because he was actively working with the PKK. Second, the violation of international law could compromise the combatant status of the PKK and so jeopardize Hillier as a lawful combatant. Due to the limited extent of the incident, the PKK soldiers would likely retain the status of combatants and be charged with a war crime. However, there is no mention in the book of the PKK taking appropriate steps to discipline the guilty soldiers internally, suggesting that the responsible commanders of the PKK are accepting of such behavior. As a result, the PKK would lack the second condition of the combatant definition under AP I, would not be lawful combatants, and could be subject to criminal prosecution. As such, foreign fighters affiliated with the PKK would also not be considered lawful combatants. This was a startling development for Hillier, which exposed him to criminal liability because the armed conflict exception would not be applicable. It was important for him to return to the Peshmerga as quickly as possible to reacquire his combatant status, which he promptly did.43

Kurdishstruggle/Alamy Stock Photo/G3F68G

Kurdish YPG special operation YAT fighters during operations on the front lines against the Islamic State in a propaganda photo released by the YPG, 10 June 2016, in Iraqi Kurdistan.


The recent conflict in the Middle East presented an interesting situation for the law regarding foreign fighters. Foreign fighters travelled from many different countries to either join ISIS or fight against them, including many Canadians. In a world where conflicts increasingly include non-state actors and widespread use of social media, it is likely that foreign fighters, including Canadians, will be prevalent on the battlefields in the future.

The terrorism offences under the Criminal Code created numerous potential criminal charges for those affiliated with terrorist groups, which could be operating as belligerents to an armed conflict. However, in cases where an armed conflict exists, the terrorism provisions would not apply as long as foreign fighters were lawful combatants respecting international law. Under international law, foreign fighters may be considered combatants in an armed conflict if they are part of an organized group that respects international law. As combatants, they would evade criminal liability as long as they do not participate in violations of international law, such as genocide, crime against humanity, or war crimes.

By travelling to Kurdistan to fight ISIS, Dillon Hillier took a serious risk. He put himself into a very dangerous situation, but he also exposed himself to potential criminal liability, especially by joining the PKK. Hillier may not have known it at the time, but he avoided criminal sanction because he did not participate in terrorist activities while fighting with the PKK, and because he was a lawful combatant in an armed conflict as part of the Peshmerga. The adventure described by Dillon Hillier in his recent book showed that the current laws applicable to foreign fighters have a common denominator: compliance with international law.

Michael Wickson is a former Infantry Officer who currently lives in Edmonton with his wife and daughter. He holds a BSc from the University of Calgary, a BMAS from the Royal Military College of Canada, and a JD from the University of Alberta. This submission was adapted from a term paper for a course on International Criminal Law, which was reviewed by Professor Joanna Harrington, JD, PhD.


  1. Jessica Stern & JM Berger, ISIS: The State of Terror (London: HarperCollins, 2015), pp.44-51.
  2. Craig Forcese & Leah West Sherriff. “Killing Citizens: Core Legal Dilemmas in the Targeted Killing Abroad of Canadian Foreign Fighters” (2016) 54 Can YB Intl Law 134, pp. 140-141; Christopher Anzalone. “Canadian Foreign Fighters in Iraq and Syria” (2015) 8:4 CTC Sentinel 14.
  3. John Gallagher was killed in Syria while serving with the Kurdish Peoples’ Protection Unit (YPG) in 2015, Adnan R Khan, “Canadian John Gallagher killed by Islamic State Suicide Bomber,”in MacLean’s (4 November 2015), at: ; Hanna Bohman and Shaelynn Jabs fought with the female arm of the YPG in Syria, Andrea Hucnar, “Alberta Woman back in Syria to fight ISIS militants,” CBC News (12 October 2016), at:>
  4. Dillon Hillier and Russell Hillier, One Soldier: A Canadian Soldier’s Fight against the Islamic State (Toronto: HarperCollins, 2016).
  5. Thomas Hegghammer, “The Rise of Muslim Foreign Fighters: Islam and the Globalization of Jihad” (2010/2011) 35:3 International Security 53, pp. 57-58.
  6. Being unpaid serves to differentiation foreign fighters from mercenaries, which by definition are motivated by private gain and criminals under international law, Protocol Additional to the Geneva Conventions of 12 August 1949, and Relating to the Protection of Victims of International Armed Conflicts (Protocol I), 8 June 1977, 1125 UNTS 17512, (1977) 16 ILM 1391 art 47(2)(c) (entered into force 7 December 1978) [AP I].
  7. Kari J Bodnarchuk, Kurdistan: Region under Siege (Minneapolis: Lerner Publications, 2000), p.10.
  8. Ibid.
  9. Dillon Hillier and Russell Hillier, p. 11.
  10. Mario Fumerton & Wladimir Van Wilgenurg, “Kurdistan’s Political Armies: The Challenge of Unifying the Peshmerga Forces,” Carnegie Endowment for International Peace (16 December 2015), at:
  11. Joost Jongerden. “A Spatial Perspective on Political Group Formation in Turkey after the 1971 Coup: The Kurdistan Workers’ Party of Turkey (PKK)” (2017) 5:2 Kurdish Studies 134, pp. 144-148.
  12. Eric W Schoon. “Building Legitimacy: International Dynamics and the Popular Evaluation of the Kurdistan Workers’ Party (PKK) in Turkey” (2017) 28:4-5 Small Wars & Insurgencies 734, p. 741.
  13. James M Poland. Understanding Terrorism: Groups, Strategies, and Responses. 3rd ed. (Upper Saddle River, New Jersey: Prentice Hall, 2011), pp. 125-126.
  14. “Public Safety Canada: Listed Terrorist Entities,” at: < >
  15. Criminal Code, RSC 1985, c C-46, s 6(2).
  16. Robert Cryer et al. An Introduction to International Criminal Law and Procedure, 3rd ed. (Cambridge, MA: Cambridge University Press, 2014), pp. 53-56.
  17. Ibid., pp. 56-57.
  18. Tyler Wentzell, “Canada’s Foreign Enlistment Act and the Spanish Civil War” (2017) 80 Labour/Le Travail 213, at 213.
  19. Foreign Enlistment Act, RSC 1985, c F-28 [FEA], s 3.
  20. Ibid., ss 3-5, 7, 9.
  21. Craig Forcese, & Ani Mamikon, “Neutrality Law, Anti-Terrorism, and Foreign Fighters: Legal Solutions to the Recruitment of Canadians to Foreign Insurgencies” (2015) 48 UBC L Rev 305, p. 352.
  22. Criminal Code, RSC 1985, c C-46, s 46(1).
  23. Ibid., s 46(2).
  24. Ibid., s 46(1)(c).
  25. Ibid., s 83.01.
  26. Ibid., s 83.01(1).
  27. Ibid., s 83.18(1).
  28. Ibid., s 83.01(1).
  29. Ibid., s 83.01.
  30. Interpretation Act, RSC 1985, c I-21.
  31. Prosecutor v Tadic, ICTY, Case No IT-94-1-AR72, Appeals Chamber, Decision on the Defence Motion for Interlocutory Appeal on Jurisdiction, 2 October 1995 at para 70 [Tadic].
  32. R Aubrey Davis III. “The Search for Combatant Status: Charting the Contours of Combatant Status in the Age of ISIS” (2015) 223:3 Mil L Rev 556, at 564.
  33. Ibid..
  34. Dillon Hillier and Russell Hillier, pp. 71-94.
  35. Mark David Maxwell & Sean M Watts. “’Unlawful Enemy Combatants’: Status, Theory of Culpability, or Neither?” (2007) 5 JICJ 19, at 20.
  36. Geneva Convention Relative to the Treatment of Prisoners of War, 12 August 1949, 75 UNTS 972 art 4 (entered into force 21 October 1950) [GC III], art 4(2).
  37. Ibid.
  38. Protocol Additional to the Geneva Conventions of 12 August 1949, and Relating to the Protection of Victims of International Armed Conflicts (Protocol I), 8 June 1977, 1125 UNTS 17512, (1977) 16 ILM 1391 art 47(2)(c) (entered into force 7 December 1978) [AP I], art 43.1.
  39. Ibid.
  40. Rome Statute of the International Criminal Court, 17 July 1998, 2187 UNTS 3, Can TS 2002 No 13 arts 6-8 (entered into force 1 July 2002) [Rome Statute].
  41. Dillon Hillier and Russell Hillier, p. 102.
  42. Rome Statute of the International Criminal Court, 17 July 1998, 2187 UNTS 3, Can TS 2002 No 13 arts 6-8 (entered into force 1 July 2002), arts 7-8.
  43. Dillon Hillier and Russell Hillier, p. 122.