Introduction
To date, parties to the various international and non-international armed conflicts underway throughout the Middle East have targeted a variety of critical infrastructure and resources of economic importance. An early wave of attacks by the Israel Defense Forces (IDF), for example, struck oil storage depots and energy complexes in and around Tehran. Iran responded in kind with drone strikes on oil refineries in neighboring Gulf Cooperation Council (GCC) nations that host American forces (e.g., here, here, and here).
Recently, the IDF targeted the South Pars gas field, the Iranian portion of a shared reserve between Iran and Qatar that is a major domestic and global source of liquified natural gas. Iran immediately responded with attacks on the Qatari-controlled section known as the North Dome. Other notable targets include banks, airports (e.g., here, here, and here), port facilities, desalination plants, and data centers (see analysis on data centers here).
The political significance of this pattern of tit-for-tat attacks on economically important resources and infrastructure is undeniable. Indeed, the effects are reverberating across international markets and policymaking. As a result of the collective attacks on the South Pars and North Dome gas fields, for instance, the Brent Crude international oil benchmark, already high, rose more than six percent. Considering the sensitivity of the energy market, officials are scrambling to prevent further escalation and contain an emerging global economic crisis.
Though the attacks share a common thread, they may not share the same legal footing. While reliance on public reporting always makes it difficult to reach definitive conclusions, it is unclear whether some of the objects targeted, overwhelmingly those struck by Iran, had a requisite connection to enemy military operations. This raises the question whether those attacks complied with the principle of distinction under the law of armed conflict, the cardinal rule that prohibits attacks on civilians and civilian objects.
In this essay, I provide a general overview of when critical infrastructure and other objects of logistical significance qualify as military objectives pursuant to that body of law. Considering the highly contextual nature of assessing compliance with other targeting rules, including the obligations to observe feasible precautions in the attack and to refrain from attacks expected to cause excessive collateral damage, my discussion is limited to the narrow question of when enemy logistics constitute lawful targets. The corollary question of whether attacks on objects not qualifying as military objectives could nonetheless be justified as belligerent reprisals, is likewise beyond this essay’s scope. I also do not address questions about the resort to military force (jus ad bellum) under the U.N. Charter or otherwise (including Iranian attacks on States in the region).
Background: Attacking Enemy Logistics vs Economic Warfare
Targeting enemy logistics is a timeless military strategy. From a doctrinal perspective, commanders do so with a view to degrading or disrupting one or more enemy centers of gravity (or sources of strength). Sustainment operations and the resources they provide are often key enablers, referred to doctrinally as critical capabilities or critical requirements, to those centers of gravity. By interrupting the flow of personnel and essential supplies to the battlefield, a commander can slow the adversary’s operational tempo or, ideally, force the enemy to culminate, paralyzing its ability to achieve its military objectives.
History brims with examples of expeditions, campaigns, or operations designed to undermine the enemy’s ability to support and sustain its military operations. During an early phase of the Peloponnesian War, for instance, Sparta’s invasion of Thrace resulted in the capture of Amphipolis, shrewdly cutting off a major source of timber vital to sustaining Athens’ powerful navy (Thucydides, 4.108). In 1943, Allied bombers launched from North Africa in Operation Tidal Wave conducted low-altitude bombing runs on oil refineries located near Ploesti, Romania, a critical source of military fuel used by the Axis Powers. A little over two decades later during the Vietnam War, the United States executed multiple bombing operations targeting the Ho Chi Minh Trail in hopes of disrupting North Vietnamese military resupply operations.
Targeting enemy logistics hence aims not merely to attrit enemy forces; rather, it seeks to undermine those forces indirectly by denying the sustainment upon which they depend for their ability to resist. It is critical to note that this classic stratagem is distinct from other military operations that are based on degrading other elements of national power. For instance, belligerents have long employed limited methods, including the execution of blockades and prize regimes, to wage so-called “economic warfare” on their adversaries. So long as those operations comply with the law of naval warfare or other applicable lex specialis, it is lawful for belligerents to do so (see discussion here). But insofar as military operations constitute “attacks,” as that term is understood in the law of armed conflict, the rule of distinction requires that they must be directed strictly at objects constituting “military objectives.”
Logistical Objects as Military Objectives
Military objectives are defined as “those objects which by their nature, location, purpose or use make an effective contribution to military action and whose total or partial destruction, capture or neutralization, in the circumstances ruling at the time, offers a definite military advantage” (AP I, art. 52(2)). There is widespread agreement that this definitional restatement accurately reflects customary international law applicable to both international and non-international armed conflicts (see ICRC’s Customary International Humanitarian Law (CIHL) study, practice relating to rule 8; State Department Legal Adviser Remarks 2016).
There is little question that several logistical targets in the present conflicts qualify as military objectives by their “nature” because, irrespective of their actual use, their inherent purpose or design is to contribute to military action (see Tallinn Manual 2.0, commentary to rule 100, ¶ 16). For instance, military installations providing logistical and other support services to military forces undoubtedly qualify as per se military objectives. Iran’s attack on Naval Support Activity Bahrain, which services the US Navy’s 5th Fleet, is a prime example.
Less settled is whether certain resources that are ostensibly civilian in character, but which are nonetheless essential for military operations and readily susceptible to military use, also qualify under this criterion. Yoram Dinstein, for instance, maintained that “[o]il is so vital today to modern warfare that military objectives by nature include not only military dumps of refined oil (for aircraft, warships, tanks, trucks, etc.), oil refinery facilities and petro-chemical plants, but also crude oil fields and pipelines. Indeed, ‘oil installations of every kind are in fact legitimate military objectives open to destruction by any belligerent.’” (¶ 404, quoting Leslie Green). By this view, strikes on oil fields and refineries, including those in early attacks on GCC nations, were arguably lawful.
The prevailing view, however, is that oil installations and other infrastructure that support both military forces and the civilian population qualify not as military objectives by nature but based upon their “use” or “purpose,” i.e., current or future intended use. In determining whether objects qualify as such, their so-called “dual use” is legally irrelevant. An object is either military or civilian; it cannot be both simultaneously. The decisive factor is whether the object’s present or future use makes an “effective contribution to military action” and whether targeting it would, under the circumstances, provide a “definite military advantage.”
With respect to interpretation of the definition’s first prong, the threshold for a contribution to be considered “effective” is fairly low. Further, it is well settled that a military objective’s present or future use does not need to relate to military action directly, as is the case with military equipment used during combat (Air & Missile Warfare (AMW) Manual, rule 24 and accompanying commentary). Instead, objects may qualify “through use which is only indirectly related to combat action, but which nevertheless provides an effective contribution to the military phase of a Party’s overall war effort.” (Bothe et al., pp. 365–66). There is consequent agreement that military objectives may include activities that are logistical in nature, including military utilization of transportation infrastructure (e.g., railroads, airfields, ports, etc.) or support to military action received from so-called “industries of fundamental importance” to the war effort (Bothe et al., p. 365; ICRC’s 1987 Commentary to AP I, art. 52, n. 3).
As for the second prong, an attacking party may assess definite military advantage in light of the broader context in which an attack occurs (Dinstein, ¶ 346; DoD Law of War Manual, § 5.6.7.3). An attack’s impact, in other words, need not be immediate, tactical, or geographically proximate. Attacking parties may anticipate the advantage gained from targeting an adversary’s logistical nodes to manifest at the operational or strategic levels of war, or even incrementally, so long as that expectation is “definite,” i.e., reasonable and not speculative.
The objects reportedly targeted by the United States and many of those reportedly targeted by Israel in the ongoing hostilities appear to satisfy these conditions. The IDF claims, for example, that it attacked oil storage depots and energy complexes in and around Tehran because they were being used by the Iranian military for their fuel needs. The United States similarly asserts that “the Iranian regime is using civilian ports along the Strait of Hormuz to conduct military operations that threaten international shipping,” prompting U.S. Central Command to issue an effective advance warning to civilians in those areas before launching attacks. In the attack that destroyed the Iranian equivalent of Air Force One at the Mehrabad Airport, the IDF alleges the aircraft was used by the Supreme Leader and senior military personnel for strategic military functions, including “to advance military procurement and to manage coordination with axis countries through both domestic and international flights.”
The IDF’s targeting of the al-Qard al-Hassan (AQAH) financial institution as part of its counter-Hezbollah operations in Lebanon followed a similar pattern. Although Amnesty International has called for the strikes to be investigated as possible war crimes because the de facto bank was not a lawful target, the IDF contends that Hezbollah was using funds held in its name by AQAH branches to directly purchase weapons and pay its fighters. If true, there is little question that those holdings constituted military objectives; it would be like targeting the military exchequer.
By contrast, while publicly reported information is admittedly limited, it is challenging to conclude that several objects targeted by Iran exhibited the requisite nexus to military action. Consider the attacks on the Aramco oil refinery in Saudi Arabia or the Ruwais Industrial Complex in the UAE. While oil refining and distribution facilities may be frequently regarded as military objectives through their use or purpose, there is no indication (at least not publicly available) that the industrial facilities attacked by Iran were, in fact, proximately supporting military forces, or were likely or intended to do so in the future. The same is evidently true for Iran’s attacks on, for instance, GCC airports and desalination plants.
The Iranian and IDF attacks on the South Pars and North Dome gas fields, criticized by neighboring States and the United States, are even more problematic. Natural gas has far fewer military applications compared to oil. While it can be used to produce electricity and heat, there is little evidence to suggest how the offshore fields effectively contributed to military action. While the IDF frequently provides justifications for its strikes, it has yet to do so in this instance. In my experience, one may be forthcoming.
Public reporting suggests the IDF may have conducted the attack to limit Islamic Revolutionary Guard Corps funding. That then raises the long-running debate over whether the refineries, gas fields, and other objects of economic significance may have qualified as military objectives based on their financial contributions (e.g., export revenue) to an adversary’s overall capacity to wage war. Some might (mistakenly) refer to this as the U.S. view, according to which objects contributing to “war-sustaining” capabilities are liable to attack (DoD Law of War Manual, § 5.6.6.2). As I explain in a forthcoming article in the Stockton Center’s International Law Studies, however, appreciable U.S. practice demonstrates that reference to that ambiguous term does not displace the requirement that a military objective exhibit a discernable causal connection to enemy military action. My understanding is that the Israeli position requires a similar link.
The bombing of Kharg Island by the United States was consistent with that practice. In that attack, U.S. forces deliberately struck Iranian “military targets” on the island, including naval mine and missile storage sites, “while preserving the oil infrastructure.” One might argue that the latter was spared as a practical matter to avoid the global economic consequences that surely would have resulted from neutralizing 90 percent of Iran’s oil export capability. Still, the United States has yet to subscribe to Professor Dinstein’s view that oil installations are per se military objectives (see DoD Law of War Manual, §§ 5.6.8, 5.6.8.5). And absent a nexus to military operations or qualification as a legitimate belligerent reprisal, attacking the island’s oil infrastructure would constitute a significant departure from U.S. practice respecting its war-sustaining approach in other recent conflicts. Economic objects, including those attacked by Iran or any other party, therefore do not qualify as military objectives merely because they contribute to the overall pool of resources available to its adversaries.
Strengthening the conclusion that many of Iran’s attacks are likely indiscriminate is the fact that the advantages seemingly sought thereby do not appear to be military in nature (see Tallinn Manual 2.0, commentary to rule 100, ¶ 21). Instead, Iran appears to have deliberately targeted civilian objects to inflict purely political, economic, or other costs at the domestic, regional, and international levels to achieve its objectives. But as the DoD Law of War Manual makes clear, “[d]iminishing the morale of the civilian population and their support for the war effort” does not constitute the type of advantage contemplated by the rule (§ 5.6.7.3; accord AP I, art. 51(2)). Absent a definite military advantage, the object of an attack does not qualify as a military objective.
Conclusion
Attacking enemy logistics remains a lawful and effective method of warfare so long as those operations are directed at legitimate military objectives. While many logistical objects satisfy that standard’s widely accepted criteria, attacks on infrastructure without a nexus to military operations or that seek purely political advantages risk violating the rule of distinction. In the final analysis, lawful targeting requires a disciplined, context-driven assessment that clearly separates military necessity from political or economic coercion.
The views are those of the author and do not necessarily reflect those of the United States Military Academy at West Point, the Army, or the United States Government.
– W. Casey Biggerstaff, Published courtesy of Just Security.
