A Crash Course in IHL for the Illinois Attorney

Post Authored by Teresa Dettloff

What is IHL?

International humanitarian law, or IHL, is a set of rules and regulations that apply in the context of an armed conflict. The most important goal of IHL is to minimize unnecessary suffering and destruction by diminishing the harmful effects of the ongoing conflict.

Further, the main principles of IHL include proportionality, necessity, distinction, and the prohibition of unnecessary suffering. These principles apply in the context of international armed conflicts and non-international armed conflicts. An international armed conflict occurs whenever a state uses armed force against another state, while a non-international armed conflict results when armed conflict either occurs between government authorities and organized non-state actors, or between organized, non-state actors.[1] The proportionality requirement holds that the anticipated damage to civilian property and loss of life cannot outweigh the military advantage of a certain objective. This is similar to the necessity tenant, which mandates a specific, required objective. Further, attacks in the context of an armed conflict cannot be indiscriminate, and parties must distinguish between lawful, military objectives and civilian objects.[2] A party also may not inflict unnecessary suffering on the opposing forces.

The IHL delineates who may or may not be targeted in an armed conflict. During armed conflicts, there are three categories of individuals: combatants, non-combatants, and civilians. Combatants are military personnel engaged in armed combat and may be targeted under international law.[3] Non-combatants are members of the armed forces who are not engaged in active hostilities, such as chaplains and medical personnel. Wounded combatants are considered noncombatants, and are not targetable under international law.[4] However, this category is fluid. If a noncombatant is actively hostile, these protections do not apply. Civilians are protected under international law and cannot be targeted. However, if they directly participate in hostilities, they are no longer protected.[5]

When is an attack Legal under International Law?

In order for an attack to be legal under international law, the attack in question must first have a valid military objective. Valid military objectives are objects that are, by virtue of their nature, location, purpose, or use, make an effective contribution to military action.[6] They also include objects “whose total or partial destruction, capture or deactivation, in the circumstances ruling at the time, offers a definite military advantage.” A state may carry out attacks on enemy military personnel equipment and may be subject to attack by enemy military personnel if the attack is proportional. If the attack is proportional, then it outweighs the risk of loss to civilian life or property. For example, civilian areas and civilian objects, including those indispensable to the civilian population, cannot be lawfully targeted.[7] However, if the loss is proportional to the destruction of the target, and that target is a valid military objective, then the attack is not illegal under international law.

Why does IHL matter?

IHL matters because the criminal tribunals prosecuting crimes under IHL hold individuals accountable for war crimes, even when they did not directly participate. A theory of liability recently developed under IHL is called joint criminal enterprise liability, or JCE liability. In practical terms, JCE liability allows military leaders to be held accountable for the criminal acts of their subordinates, even if they never actively participated in committing the crimes. JCE liability emerged through case law developed in the International Criminal Tribunal for the Former Yugoslavia (“ICTY”). [8] IHL does not require any evidence that an individual physically participated in the crimes committed.[9] Through the ICTY, the IHL created a ground of liability, in order to hold individuals committing war crimes on a massive scale during an armed conflict responsible. Without IHL, there would not be a forum to bring the crimes that occur in armed conflict to light. There also would not be enough jurisprudence to develop theories, such as JCE liability, that hold others accountable for certain war crimes.


[1] Prosecutor v. Tadic, Case No. IT-94-1-T, Decision on the Defence Motion for Interlocutory Appeal on Jurisdiction, ¶ 70 (Int’l Crim. Trib. for the Former Yugoslavia Oct. 2, 1995).

[2] See 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; Chapter 1, Art. 48.

[3] Id.

[4]  See Geneva Convention IV.

[5] Yoram Dinstein, The Conduct of Hostilities Under the Law of International Armed Conflict, 29 (Cambridge University Press 2004); Protocol Additional to the Geneva Conventions of 12 August 1949, Art. 51(3).

[6] Yoram Dinstein, supra note 5, at 87-88.

[7] See Geneva Convention IV, Article 51.

[8] Guilia Bigi, Joint Criminal Enterprise in the Jurisprudence of the International Criminal Tribunal for the Former Yugoslavia and the Prosecution of Senior Political and Military Leaders: The Krajisnik Case, 14 Max Planck Y.B. of United Nations L. 53 (2010).

[9] Joint criminal enterprise, Legal Info. Inst., https://www.law.cornell.edu/wex/joint_criminal_enterprise.

About the Author:

Teresa Detloff

Teresa is an associate at Brennan Burtker LLC, focusing her practice on medical malpractice defense. Teresa is a graduate of Loyola University Chicago School of Law, where she served as a lead article editor for the law journal. Teresa currently serves as a member of the advocacy committee for the United Nations Association Chicago chapter.

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