Abstract
The principle of proportionality demands that a war (or action in war) achieve more goods than bads. In the philosophical literature there has been a wealth of work examining precisely which goods and bads may count toward this evaluation. However, in all of these discussions there is no mention of one of the most certain bads of war, namely the psychological harm(s) likely to be suffered by the combatants who ultimately must fight and kill for the purposes of winning in conflict. This paper argues that harms to one’s own soldiers must be included in proportionality judgments, and goes on to argue that one of the most significant harms one’s soldiers face are the psychological stresses and traumas associated with combat. The arguments draw on a growing wealth of psychological literature exploring the connections between combatancy and psychological trauma, and highlight, in particular, the uniquely negative impact which killing has on a combatant’s mental well-being. The paper concludes that these factors place an almost certain and rather weighty negative weight in any proportionality calculations concerning wars with ground combatants who must fight “up close and personal”, and that for more remote warfighters, there is also evidence to show that they may suffer deep psychological harm as a result of their combat roles as well. The argument, however, does not attempt to demonstrate that these factors render war impermissible. Rather, it merely shows that these harms, or bads, which can be quite significant, must be factored into our considerations of proportionality. The arguments themselves are rather uncontroversial, but they bring to light an element in the moral calculus which is sadly overlooked in most discussions of the ethics of war.
Similar content being viewed by others
Explore related subjects
Discover the latest articles, news and stories from top researchers in related subjects.Notes
The exact ratio of goods to bads demanded is a contested issue, but in all accounts it is taken for granted that there must at least be more good than bad achieved, with most accounts holding that there must be “sufficiently” or “‘significantly” more goods achieved than bads.
Geneva Protocol I Additional to the Geneva Conventions (hereafter AP I), Art. 57.2.iii, found in Roberts and Guelff (2004, p. 453)
For recent definitional and foundational work on moral injury, as well as its relation to post-traumatic stress disorder and other psychological harms associated with combatancy, see, e.g., Hoyt (2023), Connelly (2023), Sherman (2023), Talbert and Wolfendale (2023) and MacIntosh (2023). More generally, see McDaniel et al. (2023), as well as the recent special issue dedicated to moral injury in Aether: A Journal of Strategic Airpower and Spacepower (Volume 2.3).
See, most notably, Article 57.2.a.iii of Geneva Protocol I Additional to the Geneva Conventions (hereafter AP I), and AP I, Art. 50.5.b, found in Roberts and Guelff (2004, pp. 453, 449) respectively.
Hurka (2005, 2008) and Shue (2018) discuss proportionality in a way that seems to include harms to all individuals, and by extension then, friendly combatants as well. However, these discussions generally do not give explicit treatment to friendly harms, but rather focus on a totalist accounting of harm.
The cause may not be enough to justify way (cf. Rodin, 2002), but an unjustified act of aggression against the territorial sovereignty of a state provides at least a fair degree of justification for harmful responses to be employed.
It should be noted though that killing in particular, and combatancy in general, can lead to a variety of psychological harms besides those associated with PTSD. Some of these other harms will be discussed in Sect. 4.1 below.
See also MacNair (2002a) for extensive elaboration and further exploration of these findings.
Maguen et al. (2013, p. 346). These findings of Maguen et al. (2013) may appear to conflict with those of Fontana and Rosenheck (1999). However, the work of Fontana and Rosenheck (1999) only looked at the impact of various factors on the development of PTSD in general, and not at the precise symptomatology or severity of a PTSD diagnosis. As such, these results are not at odds with one another.
Note that the cited studies only differentiated between combat and non-combat veterans, but did not include differential analysis between different types of combatants (e.g. infantrymen, artillerymen, airmen, etc.). Such differences in how one fights (and kills) are likely to affect the prevalence of PTSD, as well as its symptomatology, and there is therefore a need for such differential research to be undertaken.
American Psychiatric Association (1994, p. 429). Note that there are differences between the DSM-IV and DSM-V with regards to diagnosis of PTSD. These differences, however, do not alter the core aspects of PTSD symptomatology being discussed here.
See also the brief discussion of moral injury in Sect. 1 above, as well as the citations in footnote 5.
Scioli et al. (2010, p. 353), quoting the findings of Sherman et al. (2006). Note that there may be hidden correlates to these particular values, as it is possible that veterans who are more likely to kill (and hence more likely to suffer from PTSD) may already be more violence-prone. This is an area worthy of further study. That being said, the relation between PTSD and interpersonal violence in general is well corroborated across independent research (see citations above).
It is worth noting that revisionists’ focus on liability in proportionality judgments naturally removes discussion of “enemy” and “friendly” combatants from the debate, as these markers are largely irrelevant to their core position.
Ziegler and Otzari (2012) explicitly discuss harm to friendly combatants and proportionality, but their arguments rely on deeply suspect moral and legal categories, especially the characterization of some civilians as “enemy civilians” (a view which is unsubstantiated in either ethics or law).
Physical harms can also have long-term impacts. The point here is not to undermine the magnitude of physical harm suffered by combatants, but only to make clear that all harms can be significant, and in some cases debilitating and potentially life-threatening.
One may ask whether there are any concrete cases of wars traditionally considered just that ought to be re-evaluated as unjust based on (the actual or expected) mental injuries suffered by participating combatants. This is an interesting question, but would take us too far afield from our philosophical argument, requiring nuanced assessments of history and empirical psychology. At any rate, wars with traditionally “close” moral assessments on grounds of proportionality may present such situations (e.g., the Falklands War).
Chappelle et al. (2012), for example, report that “[r]ates of clinical distress and PTSD were higher among RPA [remotely piloted aircraft] operators (20% and 5%, respectively) in comparison to non-RPA airmen (11% and 2%, respectively)” (Chappelle et al., 2012, p. 1). Chapa (2017) provides insightful exploration of some of the ethical implications of these findings.
References
American Psychiatric Association. (1994). Diagnostic and statistical manual of mental disorders: DSM-IV (4th ed.). American Psychiatric Association.
Atkins, E., & Seamone, E. R. (2023). Remote combat exposure and moral injury from drone operations: The cost of a new form of warfare. In J. T. McDaniel, E. R. Seamone, & S. N. Xenakis (Eds.), Preventing and treating the invisible wounds of war: Combat trauma, moral injury, and psychological health, ethics, national security, and the rule of law series (pp. 207–236). Oxford University Press.
Bass, G. J. (2004). Jus post bellum. Philosophy & Public Affairs, 32(4), 384–412.
Beckham, J. C., Feldman, M. E., Kirby, A. C., Hertzberg, M. A., & Moore, S. D. (1997). Interpersonal violence and its correlates in Vietnam veterans with chronic posttraumatic stress disorder. Journal of Clinical Psychology, 53(8), 859–869.
Beckham, J. C., Roodman, A. A., Barefoot, J. C., Haney, T. L., Helms, M. J., Fairbank, J. A., Hertzberg, M. A., & Kudler, H. S. (1996). Interpersonal and self-reported hostility among combat veterans with and without posttraumatic stress disorder. Journal of Traumatic Stress, 9(2), 335–342.
Bronner, B. (2019). Intention, Prevention, and the Just War. Ph.D. Thesis, Rutgers University.
Campo, J. L. (2015). From a distance: The psychology of killing with remotely piloted aircraft. Technical report.
Chapa, J. O. (2017). Remotely piloted aircraft, risk, and killing as sacrifice: The cost of remote warfare. Journal of Military Ethics, 16(3–4), 256–271.
Chappelle, W., McDonald, K., Thompson, B., & Swearengen, J. (2012). Prevalence of high emotional distress and symptoms of post-traumatic stress disorder in US Air Force active duty remotely piloted aircraft operators: (2010 USAFSAM survey results). Technical report.
Connelly, D. A. (2023). Conceptualizations of war and moral injury: Implications for commanders and therapists. Aether, 2(3), 86–100.
Davidovic, J. (2018). Proportionality and necessity in bello. In L. May (Ed.), The Cambridge handbook of the just war (pp. 167–185). Cambridge University Press.
Fontana, A., & Rosenheck, R. (1999). A model of war zone stressors and posttraumatic stress disorder. Journal of Traumatic Stress, 12(1), 111–126.
Fontana, A., & Rosenheck, R. (2004). Trauma, change in strength of religious faith, and mental health service use among veterans treated for PTSD. Journal of Nervous & Mental Disease, 192(9), 579–584.
Foy, D. W., Sipprelle, R. C., Rueger, D. B., & Carroll, E. M. (1984). Etiology of posttraumatic stress disorder in Vietnam veterans: Analysis of premilitary, military, and combat exposure influences. Journal of Consulting and Clinical Psychology, 52(1), 79–87.
Frowe, H. (2014). Defensive killing. Oxford University Press.
Gardam, J. (2004). Necessity. Proportionality and the use of force by states. Cambridge University Press.
Gardam, J. G. (1993). Proportionality and force in international law. American Journal of International Law, 87(3), 391–413.
Gellis, L. A., Gehrman, P. R., Mavandadi, S., & Oslin, D. W. (2010). Predictors of sleep disturbances in Operation Iraqi Freedom/Operation Enduring Freedom veterans reporting a trauma. Military Medicine, 175(8), 567–573.
Goodman, R. (2013). The power to kill or capture enemy combatants. European Journal of International Law, 24(3), 819–853.
Gravel, C. (2019). Remote warfare force protection: Accounting for non-kinetic threats and risks. Technical report.
Grossman, D. (2009). On killing: The psychological cost of learning to kill in war and society (2nd ed.). Back Bay Books.
Haque, A. A. (2013). Proportionality (in war). In H. LaFollette (Ed.), International encyclopedia of ethics (pp. 4168–4175). Blackwell.
Haque, A. A. (2017). Law and morality at war. Oxford University Press.
Hoge, C. W., Castro, C. A., Messer, S. C., McGurk, D., Cotting, D. I., & Koffman, R. L. (2004). Combat duty in Iraq and Afghanistan, mental health problems, and barriers to care. New England Journal of Medicine, 351(1), 13–22.
Hoge, C. W., Terhakopian, A., Castro, C. A., Messer, S. C., & Engel, C. C. (2007). Association of posttraumatic stress disorder with somatic symptoms, health care visits, and absenteeism among Iraq War veterans. American Journal of Psychiatry, 164(1), 150–153.
Hoyt, T. (2023). Moral injury: Wrestling with definitions and conceptual drift. Aether, 2(3), 60–70.
Hurka, T. (2005). Proportionality in the morality of war. Philosophy & Public Affairs, 33(1), 34–66.
Hurka, T. (2008). Proportionality and necessity. In L. May (Ed.), War: Essays in political philosophy (pp. 127–144). Cambridge University Press.
Kang, H. K., Natelson, B. H., Mahan, C. M., Lee, K. Y., & Murphy, F. M. (2003). Post-traumatic stress disorder and chronic fatigue syndrome-like illness among Gulf War veterans: A population-based survey of 30,000 veterans. American Journal of Epidemiology, 157(2), 141–148.
Kaplan, M. S., Huguet, N., McFarland, B. H., & Newsom, J. T. (2007). Suicide among male veterans: A prospective population-based study. Journal of Epidemiology & Community Health, 61(7), 619–624.
Karam, E. G., Friedman, M. J., Hill, E. D., Kessler, R. C., McLaughlin, K. A., Petukhova, M., Sampson, L., Shahly, V., Angermeyer, M. C., Bromet, E. J., de Girolamo, G., de Graaf, R., Demyttenaere, K., Ferry, F., Florescu, S. E., Haro, J. M., He, Y., Karam, A. N., Kawakami, N., … Koenen, K. C. (2014). Cumulative traumas and risk thresholds: 12-month PTSD in the World Mental Health (WMH) surveys. Depression and Anxiety, 31(2), 130–142.
Kavka, G. S. (1991). Was the gulf war a just war? Journal of Social Philosophy, 22(1), 20–29.
Keane, T. M., Fairbank, J. A., Caddell, J. M., Zimering, R. T., Taylor, K. L., & Mora, C. A. (1989). Clinical evaluation of a measure to assess combat exposure. Psychological Assessment: A Journal of Consulting and Clinical Psychology, 1(1), 53–55.
King, D. W., King, L. A., Foy, D. W., & Gudanowski, D. M. (1996). Prewar factors in combat-related posttraumatic stress disorder: Structural equation modeling with a national sample of female and male Vietnam veterans. Journal of Consulting and Clinical Psychology, 64(3), 520–531.
King, D. W., King, L. A., Gudanowski, D. M., & Vreven, D. L. (1995). Alternative representations of war zone stressors: Relationships to posttraumatic stress disorder in male and female Vietnam veterans. Journal of Abnormal Psychology, 104(1), 184–196.
Kretzmer, D. (2013). The inherent right to self-defence and proportionality in jus ad bellum. European Journal of International Law, 24(1), 235–282.
Kulka, R. A., Schlenger, W. E., Fairbank, J. A., Hough, R. L., Jordan, B. K., Marmar, C. R., & Weiss, D. S. (1990a). The national Vietnam veterans readjustment study: Tables of findings and technical appendices. Brunner/Mazel.
Kulka, R. A., Schlenger, W. E., Fairbank, J. A., Hough, R. L., Jordan, B. K., Marmar, C. R., & Weiss, D. S. (1990b). Trauma and the Vietnam war generation: Report of findings from the national Vietnam veterans readjustment study. Brunner/Mazel.
Laufer, R. S., Gallops, M. S., & Frey-Wouters, E. (1984). War stress and trauma: The Vietnam veteran experience. Journal of Health and Social Behavior, 25(1), 65–85.
Lazar, S. (2015). Sparing civilians. Oxford University Press.
Lew, H. L., Otis, J. D., Tun, C., Kerns, R. D., Clark, M. E., & Cifu, D. X. (2009). Prevalence of chronic pain, posttraumatic stress disorder, and persistent postconcussive symptoms in OIF/OEF veterans: Polytrauma clinical triad. Journal of Rehabilitation Research & Development, 46(6), 697–702.
Litz, B. T., Stein, N., Delaney, E., Lebowitz, L., Nash, W. P., Silva, C., & Maguen, S. (2009). Moral injury and moral repair in war veterans: A preliminary model and intervention strategy. Clinical Psychology Review, 29(8), 695–706.
MacIntosh, D. (2023). Posttraumatic stress disorder weaponized: A theory of moral injury. In J. T. McDaniel, E. R. Seamone, & S. N. Xenakis (Eds.), Preventing and treating the invisible wounds of war: Combat trauma, moral injury, and psychological health, ethics, national security, and the rule of law series (pp. 175–206). Oxford University Press.
MacNair, R. (2002). Perpetration-induced traumatic stress: The psychological consequences of killing. Authors Choice Press.
MacNair, R. M. (2002). Perpetration-induced traumatic stress in combat veterans. Peace and Conflict: Journal of Peace Psychology, 8(1), 63–72.
Maguen, S., Lucenko, B. A., Reger, M. A., Gahm, G. A., Litz, B. T., Seal, K. H., Knight, S. J., & Marmar, C. R. (2010). The impact of reported direct and indirect killing on mental health symptoms in Iraq War veterans. Journal of Traumatic Stress, 23(1), 86–90.
Maguen, S., Madden, E., Bosch, J., Galatzer-Levy, I., Knight, S. J., Litz, B. T., Marmar, C. R., & McCaslin, S. E. (2013). Killing and latent classes of PTSD symptoms in Iraq and Afghanistan veterans. Journal of Affective Disorders, 145(3), 344–348.
Maguen, S., Metzler, T. J., Litz, B. T., Seal, K. H., Knight, S. J., & Marmar, C. R. (2009). The impact of killing in war on mental health symptoms and related functioning. Journal of Traumatic Stress, 22(5), 435–443.
Maguen, S., Vogt, D. S., King, L. A., King, D. W., Litz, B. T., Knight, S. J., & Marmar, C. R. (2011). The impact of killing on mental health symptoms in Gulf War veterans. Psychological Trauma: Theory, Research, Practice, and Policy, 3(1), 21.
Mayer, C. (2013). Minimizing harm to combatants: Nonlethal weapons, combatants’ rights, and state responsibility. In F. Allhoff, N. G. Evans, & A. Henschke (Eds.), Routledge handbook of ethics and war: Just war theory in the 21st century (pp. 301–311). Routledge.
McDaniel, J. T., Seamone, E. R., & Xenakis, S. N. (Eds.). (2023). Preventing and treating the invisible wounds of war: Combat trauma, moral injury, and psychological health. Ethics, National Security, and the Rule of Law SeriesOxford University Press.
McMahan, J. (2009). Killing in war. Oxford University Press.
McMahan, J. (2013). Proportionate defense. Journal of Transnational Law & Policy, 23, 1–36.
McMahan, J. (2015). Proportionality and time. Ethics, 125(3), 696–719.
McMahan, J. (2017). Proportionate defense. In J. D. Ohlin, L. May, & C. Finkelstein (Eds.), Weighing lives in war (pp. 131–154). Oxford University Press.
McMahan, J. (2018). Proportionality and necessity in Jus in Bello. In S. Lazar & H. Frowe (Eds.), The Oxford handbook of ethics of war (pp. 418–439). Oxford University Press.
McMahan, J., & McKim, R. (1993). The just war and the gulf war. Canadian Journal of Philosophy, 23(4), 501–541.
Mellow, D. (2006). Counterfactuals and the proportionality criterion. Ethics & International Affairs, 20(4), 439–454.
Milliken, C. S., Auchterlonie, J. L., & Hoge, C. W. (2007). Longitudinal assessment of mental health problems among active and reserve component soldiers returning from the Iraq War. Jama, 298(18), 2141–2148.
Moellendorf, D. (2011). Jus ex bello in Afghanistan. Ethics & International Affairs, 25(2), 155–164.
Moellendorf, D. (2015). Two doctrines of jus ex bello. Ethics, 125(3), 653–673.
Mollendorf, D. (2008). Jus ex bello. Journal of Political Philosophy, 16(2), 123–136.
Nazarian, D., Kimerling, R., & Frayne, S. M. (2012). Posttraumatic stress disorder, substance use disorders, and medical comorbidity among returning US veterans. Journal of Traumatic Stress, 25(2), 220–225.
Neylan, T. C., Marmar, C. R., Metzler, T. J., Weiss, D. S., Zatzick, D. F., Delucchi, K. L., Wu, R. M., & Schoenfeld, F. B. (1998). Sleep disturbances in the Vietnam generation: Findings from a nationally representative sample of male Vietnam veterans. American Journal of Psychiatry, 155(7), 929–933.
Orend, B. (2000). Jus post bellum. Journal of Social Philosophy, 31(1), 117–137.
Orend, B. (2007). Jus post bellum: The perspective of a just-war theorist. Leiden Journal of International Law, 20(3), 571–591.
Pietrzak, R. H., Goldstein, R. B., Southwick, S. M., & Grant, B. F. (2011). Prevalence and axis I comorbidity of full and partial posttraumatic stress disorder in the United States: Results from wave 2 of the National Epidemiologic Survey on alcohol and related conditions. Journal of Anxiety Disorders, 25(3), 456–465.
Pietrzak, R. H., Johnson, D. C., Goldstein, M. B., Malley, J. C., & Southwick, S. M. (2009). Psychological resilience and postdeployment social support protect against traumatic stress and depressive symptoms in soldiers returning from Operations Enduring Freedom and Iraqi Freedom. Depression and Anxiety, 26(8), 745–751.
Price, M., Gros, D. F., Strachan, M., Ruggiero, K. J., & Acierno, R. (2013). The role of social support in exposure therapy for Operation Iraqi Freedom/Operation Enduring Freedom veterans: A preliminary investigation. Psychological Trauma: Theory, Research, Practice, and Policy, 5(1), 93–100.
Renshaw, K. D., Rodrigues, C. S., & Jones, D. H. (2008). Psychological symptoms and marital satisfaction in spouses of Operation Iraqi Freedom veterans: Relationships with spouses’ perceptions of veterans’ experiences and symptoms. Journal of Family Psychology, 22(4), 586–594.
Roberts, A., & Guelff, R. (Eds.). (2004). Documents on the laws of war (3rd ed.). Oxford University Press.
Rodin, D. (2002). War and self-defense. Clarendon Press.
Sareen, J., Cox, B. J., Stein, M. B., Afifi, T. O., Fleet, C., & Asmundson, G. J. (2007). Physical and mental comorbidity, disability, and suicidal behavior associated with posttraumatic stress disorder in a large community sample. Psychosomatic Medicine, 69(3), 242–248.
Schlenger, W. E., Corry, N. H., Williams, C. S., Kulka, R. A., Mulvaney-Day, N., DeBakey, S., Murphy, C. M., & Marmar, C. R. (2015). A prospective study of mortality and trauma-related risk factors among a nationally representative sample of Vietnam veterans. American Journal of Epidemiology, 182(12), 980–990.
Scioli, E. R., Otis, J. D., & Keane, T. M. (2010). Psychological problems associated with Operation Enduring Freedom/Operation Iraqi Freedom deployment. American Journal of Lifestyle Medicine, 4(4), 349–359.
Seal, K. H., Bertenthal, D., Miner, C. R., Sen, S., & Marmar, C. (2007). Bringing the war back home: Mental health disorders among 103,788 US veterans returning from Iraq and Afghanistan seen at Department of Veterans Affairs facilities. Archives of Internal Medicine, 167(5), 476–482.
Shalev, A., Liberzon, I., & Marmar, C. (2017). Post-traumatic stress disorder. New England Journal of Medicine, 376(25), 2459–2469.
Sherman, M. D., Sautter, F., Jackson, M. H., Lyons, J. A., & Han, X. (2006). Domestic violence in veterans with posttraumatic stress disorder who seek couples therapy. Journal of Marital and Family Therapy, 32(4), 479–490.
Sherman, N. (2023). The look and feel of moral injury. In J. T. McDaniel, E. R. Seamone, & S. N. Xenakis (Eds.), Preventing and treating the invisible wounds of war: Combat trauma, moral injury, and psychological health, ethics, national security, and the rule of law series (pp. 131–153). Oxford University Press.
Shue, H. (2018). Last resort and proportionality. In S. Lazar & H. Frowe (Eds.), The Oxford handbook of ethics of war (pp. 260–276). Oxford University Press.
Steinhoff, U. (2017). Proportionality in self-defense. The Journal of Ethics, 21(3), 263–289.
Talbert, M., & Wolfendale, J. (2023). Moral injury, moral suffering, and moral health. In J. T. McDaniel, E. R. Seamone, & S. N. Xenakis (Eds.), Preventing and treating the invisible wounds of war: Combat trauma, moral injury, and psychological health, ethics, national security, and the rule of law series (pp. 154–174). Oxford University Press.
Tomlin, P. (2019). Subjective proportionality. Ethics, 129(2), 254–283.
Venable, H. P. (2023). Living with killing: World War II US bomber crews. Aether, 2(3), 43–59.
Wilcox, S. (2010). Social relationships and PTSD symptomatology in combat veterans. Psychological Trauma: Theory, Research, Practice, and Policy, 2(3), 175–182.
Ziegler, R., & Otzari, S. (2012). Do soldiers’ lives matter: A view from proportionality. Israel Law Review, 45(1), 53–70.
Acknowledgements
Many thanks to the Research Foundation - Flanders, whose support enabled me to conduct this research. I must also thank the participants of the 2023 annual conference of the European International Society for Military Ethics, as well as the anonymous referees of this journal, whose comments and discussion allowed me to clarify certain core points. Finally, as always, I must thank my wife Anna for giving the day to day support most crucial for getting any of this work done.
Funding
This work was supported by the Research Foundation - Flanders (FWO), under PhD Fellow research Grant #1187718N.
Author information
Authors and Affiliations
Contributions
I am the sole author of this manuscript.
Corresponding author
Ethics declarations
Conflict of interest
The authors declare that they have no conflict of interest.
Additional information
Publisher's Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Rights and permissions
Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
About this article
Cite this article
Wood, N.G. Proportionality and combat trauma. Philos Stud 181, 513–533 (2024). https://doi.org/10.1007/s11098-024-02100-2
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11098-024-02100-2