Application of the Principle of Military Advantage in Determining Proportionality


| Jan 23, 2024

Military advantage

This post examines the concept of “concrete and direct military advantage” used for purposes of applying proportionality rules in targeting. It concludes that military advantage may be based on broader operational advantages and is not limited to immediate tactical gains. I further observe that the proportionality provisions of Additional Protocol I (AP I) to the 1949 Geneva Conventions cannot be mechanistically applied to non-international armed conflicts.

The Terms “Concrete and Direct Military Advantage”

The principle of proportionality applies when civilian casualties and/or damage to civilian objects may foreseeably result from attacks on military objectives. The fact that extensive civilian casualties are anticipated as a result of an attack does not make that attack illegal. Rather, proportionality requirements are violated only when expected civilian casualties and damage to civilian objects are excessive in relation to the “concrete and direct military advantage anticipated” (AP I, arts. 51(5)(b), 57(2)(b)).

Interpretation of the term “concrete and direct military advantage” is therefore of utmost importance in undertaking proportionality analyses. This may be illustrated by the following simplified hypothetical, which is obviously relevant to the current conflict in Gaza. Assume an attack is directed against a single section of a 350-mile long military tunnel system as part of a long term coordinated operation against the entire system. The relevant inquiry is whether incidental civilian casualties anticipated from the attack must be balanced against: (a) the tactical objective of destroying a single section of the tunnel system; or (b) the operational objective of destroying the entire tunnel system. A larger number of civilian casualties may be deemed proportional if it is permissible to use the more substantial operational objective.

The International Committee of the Red Cross (ICRC) 1987 Commentary on Article 57 AP I states that the term “concrete and direct” was used “to indicate that the advantage must be substantial and relatively close, and that advantages which are hardly perceptible and those which would only appear in the long term should be disregarded” (para. 2209). Accordingly, the only permissible military advantage in the above hypothetical would likely be the tactical objective of destroying a single segment of the tunnel.

However, the Commentary‘s position appears not to reflect customary international law. Many prominent States have adopted a broader interpretation in which military advantage refers to the “advantage anticipated from the attack as a whole and not only from isolated or particular parts of an attack” (ICRC, Customary International Humanitarian Law (IHL) Study, rule 14). The ICRC casebook, How Does Law Protect in War?, states that the term “attack as whole” means that the individual attacks need not be directly connected (vol. 1, ch. 9, p. 5). Thus, the “attack as a whole” language supports an interpretation of military advantage that extends to broader operational objectives.

Other authorities widen the definition of military advantage to encompass even broader campaign and strategic objectives. The 2022 U.S. Army Judge Advocate General’s Corps Operational Law Handbook states that “balancing between incidental damage to civilian objects and incidental civilian casualties may be done on a target-by-target basis, but also may be done in an overall sense against campaign objectives” (p. 60). Meanwhile, section of the U.S. Department of Defense (DoD) Law of War Manual states that “in assessing the military advantage of attacking an object, one may consider the entire war strategy rather than only the potential tactical gains from attacking that object.” And section 415 of Canada’s Joint Doctrine Manual, Law of Armed Conflict, broadens military advantage to include the advantage anticipated from the “military campaign” when “considered as a whole.” The Eritrea-Ethiopia Claims Commission stated that military advantage refers to the advantage anticipated from the “armed conflict as a whole” (Partial Award, Western Front, Aerial Bombardment, para. 113). It is evident that military advantage may be based on operational objectives if, as some authorities assert, military advantage may be based on even broader campaign or strategic objectives.

The 1998 Rome Statute, which imposes criminal penalties for violations of proportionality rules, buttresses the broad reading as well. Article 8(2)(b)(iv) of the Rome Statute states that incidental civilian losses must be balanced against the “concrete and direct overall military advantage” (emphasis added). The International Criminal Court elaborates on this point by stating that the military advantage “may or may not be temporally or geographically related to the object of the attack” (ICC, Elements of Crimes, Art. 8(2)(b)(iv), n. 6). It therefore appears that military advantage may be based on operational objectives when defending against criminal charges alleging violations of proportionality rules.

The ICRC itself appears to have backtracked on any requirement to limit military advantage to the immediate tactical environment. The ICRC stated that the Rome Statute’s addition of the word “overall” in describing military advantage did not change existing law (ICRC, Customary IHL Study, rule 14). Moreover, the ICRC stated that a military advantage “that can be felt over a lengthy period of time and affect military action in areas other than the vicinity of the target itself” was already encompassed by “the existing wording of Additional Protocol I and the substantive rule of customary international law . . .” (ICRC Customary IHL Study, rule 156).

The increased risk to civilians from basing military advantage on operational objectives may be minimized by estimating the civilian losses anticipated to result from the entire operation, and then comparing that aggregated estimate to the anticipated operational advantage. Nonetheless, it must be acknowledged that greater uncertainty exists in estimating civilian losses in a major multi-faceted operation than would be the case if the estimate were based on a relatively small number of closely connected attacks. Moreover, the inherent subjectivity that exists when balancing innocent civilian casualties against military advantages is further amplified when the scope of the military advantage is expanded.

Any interpretation of military advantage that extends beyond the immediate tactical environment may be criticized on the basis that it could allow for higher civilian casualties. Nonetheless, it is important to distinguish the law as it is from the law as one may believe it should be. In essence, the option to base military advantage on broader operational objectives limits the scope of the protection provided to the civilian population by the proportionality principle.

Applicability of AP I Proportionality Principles to Non-International Conflicts

The proportionality principles contained in AP I Articles 51(5)(b) and 57(2)(b) are particularly unsuited for conflicts involving non-State actors. In the case of the conflict in Gaza, Hamas did not seek military advantage in the sense recognized by international law, such as the occupation of territory or the destruction of Israel’s military capabilities. Rather, the October 7, 2023 attacks were acts of terror directed primarily against civilians.

This raises the issue of whether Israel’s overarching objective of preventing attacks on Israeli civilians may be included within the definition of military advantage. It is unclear whether protection of civilians and other non-military assets serve a military purpose (see Université Laval, The Principle of Proportionality in the Rules Governing the Conduct Of Hostilities Under IHL, p. 29-30). The U.S. position is that “civilians at risk if the attack is not taken” may be considered in the proportionality evaluation (DoD, Law of War Manual, § 5.12.3). However, it is unclear whether this is based on general moral considerations, or whether the protection of “civilians at risk if the attack is not taken” is encompassed within the scope of military advantage during non-international armed conflict.

It would seem morally abhorrent if the proportionality analysis protected civilians in Gaza without also taking into consideration the protection of civilians in Israel. It is for this reason that the concept of military advantage as delineated in AP I represents an inadequate framework where the primary objective of a non-State actor is to terrorize the civilian population during non-international armed conflict.

Proportionality rules established by AP I are not applicable in their entirety to non-international conflicts. As noted by International Criminal Tribunal for the former Yugoslavia in Prosecutor v. Tadic, the extension of the rules governing international conflicts “has not taken place in the form of a full and mechanical transplant of those rules to internal conflicts; rather, the general essence of those rules, and not the detailed regulation they may contain, has become applicable to internal conflicts” (para. 126).

Indeed, there is doubt that State parties to Additional Protocol II to the Geneva Conventions of 12 August 1949, and relating to the Protection of Victims of Non-International Armed Conflicts (AP II) intended to replicate in the non-international sphere the proportionality criteria established by AP I. This is illustrated by the omission of a codified proportionality test in AP II, which governs certain qualifying forms of non-international conflict. As noted by the DoD Manual, “States negotiated and adopted AP I and AP II at the same diplomatic conference, and the omission from AP II of restrictions present in AP I may, to some extent, reflect States’ views that such restrictions were not applicable in non-international armed conflict” (§

The distinction between international and non-international conflicts in applying proportionality principles is further evidenced by the Rome Statute. Article 8(2)(b)(iv) of the Rome Statute criminalizes intentional violations of AP I proportionality rules in the international context. However, intentional violation of proportionality rules is not listed as a war crime in the context of non-international conflicts (see Article 8(2)(e)). The Rome Statute’s list of war crimes in non-international conflicts was intended to reflect customary international law as of the date of the statute’s adoption in 1998 (see Yudan Tan, The Rome Statute as Evidence of Customary International Law, Doctoral Dissertation Universiteit Leiden, p. 99-119). As such, it would appear that the proportionality criteria established by AP I may not have been reflective of customary international law to the extent that it could be wholly transplanted into non-international conflicts.

As noted above, AP II does not contain a codified proportionality principle. However, an ICRC Commentary to Article 13 of AP II is instructive. The Commentary states that proportionality is to be determined based on “the relation between the direct advantage anticipated from an attack and the harmful effects which could result on the persons and objects protected . . .” (para. 4772). The Commentary further states that “the safety measures they are obliged to take under the rule on protection will have to be developed so as to best suit each situation, the infrastructure available and the means at their disposal” (para. 4764).

The Commentary to Article 13 suggests greater flexibility in applying proportionality rules in the non-international context. Notably, the term “direct advantage” as used in the Commentary to Article 13 omits the term “military.” It cannot be assumed that this omission was inadvertent. Rather, it may have been intended to convey the possibility of taking into consideration other advantages in addition to those of a purely military nature. In other words, the protection of “civilians at risk if the attack is not taken” may be considered as an advantage when performing the proportionality analysis in the non-international context.


The wisdom of protecting innocent civilians in warfare cannot be doubted. However, this purpose is not effectively served by the proportionality principles contained in Additional Protocol I. The importation of these principles into the non-international sphere only magnifies the inefficacy of the proportionality analysis as a vehicle for civilian protection. The absence of a uniformly accepted interpretation of proportionality in both the international and non-international spheres indicates the necessity for further development of the law in this critical area.


Jeffrey Lovitky is a former member of the U.S. Army JAGC who practices law in Washington D.C. The views expressed herein are the author’s alone.



Photo credit: U.S. Army, Staff Sgt. Matthew Foster