The Army Lawyer | Issue 1 2021View PDF

null Are Mercenaries the Future of Warfare?

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Practice Notes

Are Mercenaries the Future of Warfare?

Mercenaries . . . are useless and dangerous. And if a prince holds on to his state by means of mercenary armies, he will never be stable or secure.1

Frankly, . . . we need to accept the fact that mercenaries are here to stay, and they will change warfare as we know it.2

Mercenaries have been used since the dawn of war.3 For much of history, it was preferable to rent an existing, trained force rather than going through the expense of creating one from within.4 From the mid-nineteenth century through the end of the twentieth century, as nation-states developed professional militaries, mercenaries fell out of favor. In recent years, however, there has been a tremendous resurgence in the use of mercenary forces on the battlefield.5 While Machiavelli may have discouraged their use over five-hundred years ago, many nations appear to have adopted the modern-day sentiment of Professor Sean McFate from the National Defense University: mercenaries are an accepted and growing element of warfare.

One of the most prolific users of mercenaries is Russia, which has used such groups to expand its presence and influence in various hotspots around the world. Rather than deploying large numbers of military forces into conflict zones, Russia has increasingly sent mercenaries to accomplish the mission.6 The use of these opaque forces is intended to provide plausible deniability for any involvement and to shield the Russian government from responsibility.7 These Russian efforts represent a dangerous geopolitical trend. They also present unique legal challenges in terms of state responsibility and accountability under the law of armed conflict.

In the era of great power competition, judge advocates (JAs) need to be aware of these battlefield developments. They must be prepared to provide the right context legal advice to commanders about how best to deal with these emerging forces. This article will assist in that preparation by detailing the contemporary uses of Russian mercenaries, the laws applicable to them, and recommendations for advising commanders about these groups.

Contemporary Uses of Russian Mercenaries

Ranging from the Tsarist days through the Soviet era, Russia has a long history of employing mercenaries to fight battles.8 Under Vladimir Putin’s leadership, the practice has evolved and increased.9 With Putin’s consolidation of the various security apparatuses, and an abundance of skilled military veterans following the collapse of the Soviet Union, the conditions were ripe for an expanded reliance on these quasi-state forces.10 With Russia seeking to re-emerge as a global power, mercenary groups provide low-cost options to rapidly send forces to support favored authoritarian regimes or friendly military leaders.11 Russia views these groups as particularly attractive because they operate under legal ambiguity and allow for plausible deniability. These dynamics led to the formation of numerous Russian private mercenary groups.

The most prolific of these Russian mercenary organizations is the Wagner Group.12 It is headed by Yevgeny Prigozhin, a Russian oligarch and close Putin ally.13 Wagner, like most other Russian mercenary groups, operates worldwide—despite being officially outlawed under Russian law, which prohibits mercenaries and all private military security contractors.14 Instead, Wagner is registered using a series of shell corporations located outside of Russia.15 Through its close ties to Russian Special Forces and other security service elements, Wagner has access to sophisticated weapons and intelligence.16 Its worldwide actions are coordinated with Putin’s regime to advance Russia’s national interests and expand Russian influence.17

The Wagner Group supported Russia’s efforts in Syria several years before the official entry of Russian military forces into the conflict. Wagner, operating at the time as a predecessor firm known as the Slavonic Corps, was contracted to protect Syrian military depots and various oil fields in eastern Syria. The mercenaries, however, were not simply guarding static sites. As the Islamic State of Iraq and Levant and other groups began having success against the Syrian regime, Wagner increasingly began participating alongside regime forces in offensive combat operations to retake territory.18 Even through present day, Wagner Group elements have remained engaged in these types of combat operations in Syria—thus, playing a variety of roles that complement the mission of Russian uniformed forces.19

Wagner was also instrumental in helping Russia accomplish its goals in the Ukraine. Elements of Wagner are suspected to have been associated with the “little green men” and Russian forces, both regular and irregular, who helped annex Crimea in early 2014.20 In eastern Ukraine, they engaged in some of the heaviest direct fighting against Ukrainian forces. Equipped with new Russian armored trucks and other key military items, Wagner Group elements have fought alongside separatist forces across the Donbass region.21 Russia employed these mercenaries, rather than its military, to avoid domestic scrutiny for casualties and to falsely claim all the fighters were indigenous separatists.22

Russia is further employing this mercenary model in Venezuela and across Africa as it seeks expanded influence and access to natural resources and basing rights.23 The Wagner Group is having one of its biggest impacts in Libya where it is helping a Russian ally in an ongoing civil war. The Wagner Group deployed several hundred snipers and others to Libya in 2019 to support the militia fighting against the United Nations-recognized government in Tripoli.24 The experienced mercenaries provided an immediate military advantage on the battlefield, tipping the balance in favor of the militia.25 Wagner elements even destroyed an American unmanned vehicle flying over Libya using advanced Russian-made air defense artillery.26 These actions led the commander of U.S. Africa Command to condemn Wagner as being a “destabilizing” element helping Russia expand its footprint in Africa.27

The contemporary use of mercenaries is far reaching and formidable. Russia is not alone in the use of these shadowy forces. Mercenaries have become more prevalent in various corners of the globe, including helping the government in Nigeria fight against Boko Haram, and assisting the Saudi-led coalition in Yemen.28 Given the limited pushback and relative success Russia and others have had using mercenaries, one should expect to see them employed more often in the future.

Applicable Law

With this trend of relying on mercenaries likely to continue, JAs must understand how these groups are classified under international law. Legal advisors need to provide commanders with timely advice about the complicated legal framework surrounding mercenary groups.

Under the 1907 Hague Conventions, there was no prohibition on mercenaries working for a warring nation.29 They were treated as comparable members of the nation’s official military force. The parties to the 1949 Geneva Conventions (GC) did not directly address the role of mercenaries. They did, however, potentially afford them prisoner of war status protections under the Third Geneva Convention (GC III), Article 4(a), but only if the person qualified as accompanying the armed forces of a party to the conflict.30

The first major treaty to detail the legal obligations of mercenaries is the 1977 First Additional Protocol to the Geneva Conventions [AP I].31 Article 47 of AP I prohibits a mercenary from qualifying as a lawful combatant or obtaining prisoner of war status.32 It provides a six-part definition of who qualifies as a mercenary, to include a requirement that the person must be motivated by a “desire for private gain.”33 These rules apply only in international armed conflicts. A study conducted by the International Committee for the Red Cross (ICRC) claims that Article 47 is reflective of customary international law, but the United States disagrees with that assessment.34 The Department of Defense Law of War Manual details the U.S. position that being a mercenary is not considered a crime under international law.35 The manual further explains how the United States determines whether mercenaries are disqualified from being combatants or prisoners of war simply for being paid for their services.36 The United States does, however, believe mercenaries must follow the law of armed conflict and can be tried and punished for any violations.37

While the United States does not adopt the AP I position as being customary, it is important to remember that many U.S. allies are AP I treaty members and do consider it binding law. Additionally, some U.S. partners have also signed onto a 2001 International Convention against the Recruitment, Use, Financing, and Training of Mercenaries which extended prohibitions against mercenary groups in both international and non-international armed conflicts.38 Judge advocates working in international coalitions need to be mindful of the potential for varied legal interpretations amongst the coalition partners.

The Wagner Group and other similar Russian organizations dispute being labeled as mercenaries. These groups regularly refer to themselves as private military security contractors (PMSCs) or similar descriptions.39 They claim they do not fall under the AP I six-part definition of mercenaries.40 The distinction between mercenaries and PMSCs is not always clear, but the rules for mercenaries have done little to regulate groups like Wagner. Moreover, Russia intentionally blurs these lines and takes advantage of these perceived definitional gaps.41

Given the definitional uncertainty, JAs must also focus on the rules applicable to PMSCs. Security contractors do not have a separate legal classification under international law, nor are they specifically regulated under customary international law.42 While some commentators have called this situation a “vacuum,” the members of PMSCs do, nevertheless, fall under the longstanding law of armed conflict dichotomy of being either a combatant or a civilian. Depending on their role and affiliation with a state party to the conflict, members of PMSCs could be classified under GC III, Article 4, in a few different ways.43 Legal advisors must carefully examine these factors as each of the different statuses would affect various legal aspects, such as whether the contractor would be entitled to prisoner of war status and under what situations the contractor could be targeted or detained.

In a major 2008 international effort known as the Montreux Document, states sought to address some of the perceived PMSCs legal gaps by adopting a set of best practices for PMSCs.44 Russia refused to sign onto the agreement or force its PMSCs to adhere to the practices.45 Similarly, the PMSCs’ industry created an International Code of Conduct for Private Security Service Providers for which individual firms pledge to follow international law; but, the Wagner Group has not yet committed to the code.46

Instead, Russia has purposely sought to take advantage of these legal gaps and use groups like Wagner to help it avoid state responsibility.47 Russian leadership has used extensive disinformation campaigns to consistently deny any ties to Wagner and other mercenary groups and to disavow any role in directing their activities.48 Additionally, in 2018, President Putin decreed that all information related to firms cooperating with Russian intelligence would be classified.49 This action ensured communications between Wagner and Russian officials would remain secret.50

There are many benefits for Russia if it succeeds in maintaining the allusion of separation between itself and Wagner. When Russia exclusively uses mercenary groups in an armed conflict, it can claim to not be involved in the conflict. Thereby, it might avoid scrutiny under jus ad bellum or the United Nations Charter’s non-interference principles.51 Russia’s obfuscation may also affect the character and applicable law of some non-international armed conflicts as their official entry into the conflict might otherwise transform it into an international armed conflict.52 Furthermore, under international law, the conduct of a group is attributed to the state—if the state directs or controls the group.53 Russia’s deliberate disinformation is intended to help it avoid accountability for any mercenary misconduct. Until the law potentially evolves, one should expect nations like Russia to continue to rely on groups like Wagner.54

Providing Legal Advice About Mercenary Groups

Judge advocates must be prepared for battlefield encounters with mercenary groups. Legal advisors will be expected to provide advice on the thorny legal issues about whether mercenaries can be targeted or detained. This is not a hypothetical risk. In early 2018, U.S. forces located in eastern Syria came under an armored assault from several hundred Wagner Group members operating in support of pro-Syrian regime forces.55 A four-hour firefight ensued, and estimates indicate more than one-hundred Russian mercenaries were killed in the exchange.56 With Russia expanding its mercenary presence around the world, the potential for similar interactions with U.S. forces will only increase in the future.

Given the likely interactions with mercenaries on the battlefield, JAs need to anticipate the issues related to detention and treatment of these personnel. The United States does not view the mere act of being a mercenary as a crime under international law.57 Thus, mercenaries may be afforded Prisoner of War (POW) status, but only if they meet the requirements thereof—such as being considered a member of the militia or the armed forces of the nation. Depending on the circumstances, however, there may be doubt with respect to the status of these detained mercenaries. In cases of doubt, the United States would determine through a competent tribunal (commonly referred to as an “Article 5 tribunal”) whether the personnel are entitled to POW status or should instead be treated as unprivileged belligerents.58 Article 5 tribunals provide a forum during a conflict for a detained individual to address a panel of three commissioned officers and assert whether they are entitled to POW status.59 Normally, JAs serve as non-voting recorders for these tribunals; and, as part of the operational planning effort, they play a key role in the planning and developing of them. Furthermore, mercenaries—whether deemed unprivileged belligerents, POWs, or (regardless of status) having committed violations of the law of armed conflict—can potentially be prosecuted for war crimes. Judge advocates would undoubtedly serve in critical roles if such prosecutions took place using courts-martial, military tribunals, or military commissions.

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A Soldier holds an American flag prior to the start of an oath of citizenship ceremony at Fort Knox, Kentucky. (Credit: Eric Pilgrim)

Judge advocates also have a role to play in helping America’s great power competition against Russia. America needs to highlight Russia’s illicit use of mercenaries and detail how it violates international law and facilitates corruption around the world.60 Legal advisors must be vigilant for law of armed conflict violations involving mercenary groups. Russian mercenaries have been implicated in several atrocities. For example, Wagner has been accused of torture, human rights abuses, and the killing of three reporters who were investigating their operations in the Central African Republic.61 Judge advocates can help work with commands to detail and expose the abuses of Russian mercenaries. Using that information, America can attempt to implicate Russian state responsibility and pressure Russia to reform its conduct.


Some might contend Russia’s use of mercenaries is the functional equivalent of the United States relying heavily on contractor groups, such as Blackwater, during the height of the wars in Iraq and Afghanistan. Such a comparison, however, is tremendously flawed. While the United States consistently hires legally-registered contractor firms, Wagner is a “covert creation” of the Putin regime.62 Russia intentionally obscures its connections to Wagner, but the United States publicly announces the deployment of its contractor personnel.63 Moreover, as opposed to Russia, the United States demands all armed contractors receive individual training on the law of armed conflict and the use of force.64 Although the United States has faced criticism for deploying armed contractors to the battlefield, U.S. practices differ fundamentally from those of Russia.

To prepare for the fluid combat situations of Battlefield Next, national security law professionals need to stay attuned to these emerging participants of war. It is almost assured that mercenaries will play a role in future conflicts. These contracted forces provide the ambiguity and flexibility that America’s great power competition adversaries seek, and JAs must be at the vanguard in helping identify the legal implications of these mercenary groups for their commanders and units. TAL

COL Thurnher is the Staff Judge Advocate for the 82d Airborne Division at Fort Bragg, North Carolina.


1. Niccolo Machiavelli, The Prince 42 (Oxford University Press 2008) (1513).

2. Sean McFate, The New Rules of War: Victory in the Age of Durable Disorder 125 (2019).

3. Id.

4. Id.

5. Id. at 128.

6. Candace Rondeaux, Decoding the Wagner Group: Analyzing the Role of Private Military Security Contractors in Russian Proxy Warfare 1, 6-7 (2019),

7. Anna Borshchevskaya, Russian Private Military Companies: Continuity and Evolution of the Model, Foreign Pol’y Rsch. Inst. 1 (Dec. 2019),

8. Kimberly Marten, Russia’s Use of Semi-State Security Forces: The Case of the Wagner Group, 35 Post-Soviet Affs. 181, 181 (2019).

9. Borshchevskaya, supra note 7, at 2.

10. Rondeaux, supra note 6, at 7.

11. Borshchevskaya, supra note 7, at 6.

12. Marten, supra note 8, at 184.

13. Dionne Searcey, Gems, Warlords and Mercenaries: Russia’s Playbook in Central African Republic, N.Y. Times (Sept. 30, 2019), See also Ep. 62: Wagner and Russian Private Military Contractors, Def. One (Jan. 15, 2020),

14. However, Russian law does provide some legal options for Russian oil and gas businesses, and others, to employ private security contractors to protect their overseas interests. These rules are intended to offer security protection, which is fundamentally different from what is offered by mercenary groups like Wagner. Russian firms, however, have consistently exploited gaps in these rules. Borshchevskaya, supra note 7, at 6.

15. Marten, supra note 8, at 192.

16. Hearing to Receive Testimony on United States Africa Command and United States Southern Command in Review of the Defense Authorization Request for Fiscal Year 2021 and the Future Years Defense Program: Hearing Before the S. Comm. on Armed Servs., 116th Cong. 4 (2020) (statement of Gen. Stephen J. Townsend, U.S. Army, Commander, U.S. Africa Command) [hereinafter Statement of Gen. Townsend].

17. Hearing to Receive Testimony on United States Africa Command and United States Southern Command in Review of the Defense Authorization Request for Fiscal Year 2020 and the Future Years Defense Program: Hearing Before the S. Comm. on Armed Servs. 116th Cong. 32-33 (2019) (statement of Gen. Thomas D. Waldhauser, U.S. Marine Corps, Commander, U.S. Africa Command).

18. Rondeaux, supra note 6, at 45.

19. Nathaniel Reynolds, Putin’s Not-So-Secret Mercenaries: Patronage, Geopolitics, and the Wagner Group (2019),

20. Borshchevskaya, supra note 7, at 9.

21. Marten, supra note 8, at 193.

22. Id.

23. Benoit Faucon & James Marson, Russia Leans on Mercenary Forces to Regain Global Clout, Wall St. J. (Feb. 23, 2020), Russian mercenaries have appeared in the African nations of Zimbabwe, Central African Republic, Guinea, Sudan, the Democratic Republic of Congo, and several others. See Andrew S. Weiss & Eugene Rumer, Carnegie Endowment for Int’l Peace, Nuclear Enrichment: Russia’s Ill-Fated Influence Campaign in South Africa (2019). These private groups train and fight alongside local military forces and help Russia gain tremendous influence. Searcey, supra note 13. For example, according to the U.S. Africa Command commander, the Wagner Group’s extensive influence in Central African Republic has extended to the highest levels of the government—including their president. Paul Stronski, Carnegie Endowment for Int’l Peace, Late to the Party: Russia’s Return to Africa 5-27 (2019).

24. David D. Kirkpatrick, Russian Snipers, Missiles and Warplanes Try to Tilt Libyan War, N.Y. Times, (June 18, 2020).

25. Id.; Michael Weiss & Pierre Vaux, Russia’s Wagner Mercenaries Have Moved into Libya, Daily Beast, (Sept. 28, 2019, 1:32 AM).

26. Statement of Gen. Townsend, supra note 16, at 4.

27. Id.

28. McFate, supra note 2, at 134-35. Some groups have even advocated that the United States should look to mercenaries to handle their long-standing counterinsurgency efforts in Afghanistan. Erik D. Prince, The MacArthur Model for Afghanistan, Wall St. J., (May 31, 2017),

29. Convention No. V Respecting the Rights and Duties of Neutral Powers and Persons in Case of War on Land, Oct. 18, 1907, 36 Stat. 2310; Peter W. Singer, War, Profits, and the Vacuum of Law: Privatized Military Firms and International Law, 42 Colum. J. Transnat’l L. 521, 526 (2004).

30. Geneva Convention Relative to the Treatment of Prisoners of War art. 4(a), Aug. 12, 1949, 6 U.S.T. 3316, 75 U.N.T.S. 135; Singer, supra note 29, at 526.

31. Katherine Fallah, Corporate Actors: The Legal Status of Mercenaries in Armed Conflict, 88 Int’l Rev. Red Cross 599, 603 (2006).

32. Protocol Additional to the Geneva Conventions of 12 August 1949, and Relating to the Protection of Victims of International Armed Conflicts (Protocol I) art. 47, 8 June 1977, 1125 U.N.T.S. 3 [hereinafter AP I].

33. Id. art. 47. A mercenary is a person who: “(a) is specially recruited locally or abroad in order to fight in an armed conflict; (b) does, in fact, take a direct part in the hostilities; (c) is motivated to take part in the hostilities essentially by the desire for private gain and, in fact, is promised, by or on behalf of a Party to the conflict, material compensation substantially in excess of that promised or paid to combatants of similar ranks and functions in the armed forces of that Party; (d) is neither a national of a Party to the conflict nor a resident of territory controlled by a Party to the conflict; (e) is not a member of the armed forces of a Party to the conflict; and (f) has not been sent by a State which is not a Party to the conflict on official duty as a member of its armed forces.” Id.

34. Int’l Comm. of the Red Cross, Customary International Humanitarian Law r. 108 (Jean-Marie Henckaerts & Louise Doswald-Beck eds., 2005); U.S. Dep’t of Def., DoD Law of War Manual para. 4.21 (12 June 2015) (C2, 13 Dec. 2016) [hereinafter Law of War Manual].

35. Law of War Manual, supra note 34, para. 4.21.

36. Id.

37. Id.

38. International Convention against the Recruitment, Use, Financing, and Training of Mercenaries, Oct. 20, 2001, 2163 U.N.T.S. 75. Neither the United States nor Russia have signed onto this convention. Ctr. for Human Rts. & Rule of L. Initiative, Am. Bar Ass’n, The Legal Framework Regulating Proxy Warfare 17 (2019).

39. These types of entities are also commonly referred to as private military contractors, private security contractors, or private military firms.

40. For example, they contend they perform their missions for more than merely private gain, relying on broader justifications—such as performing the missions in part for their reputation or their connection to a state. Marten, supra note 8, at 183; Borshchevskaya, supra note 7, at 4.

41. Singer, supra note 29, at 534. Rondeaux, supra note 6, at 6.

42. Louis Doswold-Beck, Private Military Companies Under International Humanitarian Law, in From Mercenaries to Market: The Rise and Regulations of Private Military Companies 115 (Simon Chesterman & Chia Lehnardt eds. 2007).

43. For example, PMSC employees could conceivably be deemed to be part of the armed forces of a party to the conflict, part of a militia, as a person who accompanies the armed forces, or as a civilian taking a direct part in hostilities. Id. at 116-27.

44. The Montreux Document was a Swiss and ICRC-led initiative. It has been adopted by more than fifty states, including the United States and several of its key allies. Int’l Comm. of the Red Cross, The Montreux Document (2009); Int’l Comm. of the Red Cross, Private Military and Security Companies: Implementation of Montreux Document (2004),

45. See Rondeaux, supra note 6, at 17.

46. Int’l Code of Conduct Ass’n, International Code of Conduct for Private Security Service Providers (2010),

47. Weiss & Rumer, supra note 23.

48. Reynolds, supra note 19; Maria Tsvetkova, Russian Clinic Treated Mercenaries Injured in Secret Wars, Reuters (Jan. 7, 2020, 6:44 AM),

49. Marten, supra note 8, at 184-85.

50. Id.

51. Colonel Shane R. Reeves & Major Ronald T. P. Alcala, Five Legal Takeaways from the Syrian War, Harv. L. Nat’l Sec. J. Online 1, 4 (2019),

52. Id.

53. G.A. Res. 56/83, annex, Responsibility of States for Internationally Wrong Acts art. 8 (Dec. 12, 2001); Ctr. for Human Rts. & Rule of L. Initiative , supra note 38, at 14-17; Reeves & Alcala, supra note 51, at 4.

54. Reeves & Alcala, supra note 51, at 4.

55. McFate, supra note 2, at 132.

56. Thomas Gibbons-Neff, How a 4-Hour Battle Between Russian Mercenaries and U.S. Commandos Unfolded in Syria, N.Y. Times (May 24, 2018),

57. Law of War Manual, supra note 34, para. 4.21.

58. U.S. Dep’t of Army, Field Manual 6-27, The Commander’s Handbook on the Law of Land Warfare para. 1-64 (Aug. 2019).

59. U.S. Dep’t of Army, Reg. 190-8, Enemy Prisoners of War, Retained Personnel, Civilian Internees and Other Detainees para. 1-6 (Oct. 1, 1997).

60. Stronski, supra note 23, at 5-27.

61. Searcey, supra note 13.

62. Reynolds, supra note 19.

63. Heidi Peters, Department of Defense Contractor and Troop Levels in Afghanistan and Iraq: 2007-2020, Congr. Rsch. Serv. 1-2 (Feb. 22, 2021); Off. of the Ass’t Sec. of Def. for Sustainment, Contractor Support of U.S. Operations in the USCENTCOM Area of Responsibility (Jan. 2021),

64. U.S. Dep’t of Def., Instr. 3020.50, Private Security Contractors (PSCs) Operating in Contingency Operations, Humanitarian or Peace Operations, or Other Military Operations or Exercises encl. 3 para. 1.a.(3)(d) (22 July 2009) (C1, 1 Aug. 2011).