This post forms the second instalment of my series on essential principles of International Humanitarian Law (IHL). The first post explored the foundational principle of distinction. We now turn to a closely related—but operationally even more demanding—rule: precautions in attack, enshrined in Article 57 AP I and customary international law. These obligations shape concrete military practice, doctrine, targeting cycles, technological design, and even procurement decisions.
Understanding precautions in attack helps explain not only why but how armed forces strive to protect civilians in real operations.
This post is divided into to parts: This first part explains why precautions in attack must not only be taken by armed forces but also matter for defense contractors. It provides an overview of the core obligations arising from Article 57 AP I and the meaning of the terms used in it. It then demonstrates how armed forces implement Article 57 AP I and how modern warfare challenges the compliance with this fundamental principle.
The second part of this post will address cyber operations and non-kinetic effects. It will also explain how cyber capabilities and artificial intelligence can be an enabler of compliance with Article 57 AP I.
Estimated reading time: 9 minutes
1. Why Precautions in Attack Matter for Defence Contractors
Although Article 57 AP I binds states, defence contractors now determine whether compliance is technically possible. Modern militaries expect systems—AI-enabled or not—to enable precautionary measures such as verification, discrimination, and attack cancellation. This makes IHL a direct design constraint, not a distant legal concept.
1.1 Legal Requirements Become Also Technical Requirements
Precautions in attack depend on what the system allows operators to see, understand, and decide under accelerating timelines. As warfare speeds up, this means IHL duties translate into engineering obligations:
- sensor fidelity supporting reliable target verification,
- data architectures that preserve traceability and integrity
- decision-support interfaces that lift the fog of war
- autonomy that remains predictable and controllable
- fail-safe behaviors that reduce—not increase—civilian risk.
If systems fail at these points, Article 57 compliance becomes impossible in practice.
1.2 Compliance-by-Design Is a Competitive Advantage
Nations now integrate civilian-harm mitigation and IHL alignment into acquisition rules (e.g., U.S. CHMR-AP, emerging NATO standards). Procurement authorities increasingly ask:
- Does the system support lawful targeting?
- Does it enable human judgement?
- Does it provide transparent logs and uncertainty metrics?
Contractors who can answer “yes” with demonstrable design choices gain a decisive competitive edge.
1.3 Why Defense Contractors Cannot Leave IHL Compliance to Their Legal Department
Legal teams interpret obligations; they cannot retrofit compliance once the system architecture is fixed. IHL alignment depends on early decisions about:
- model training and data curation.
- human-machine interaction and cognitive load.
- override and abort mechanisms.
- risk visualization and uncertainty modelling.
Late-stage fixes lead to delays, redesign costs, failed certification, and diminished customer trust.
IHL is no longer a legal afterthought. It is a design parameter.
Contractors who embed specialized IHL expertise early are faster, safer, more trusted—and more competitive.
2. What Article 57 Requires
2.1 The Rule
Article 57 AP I requires armed forces to take “constant care” and “all feasible precautions” to spare civilians and civilian objects during attacks. Key duties include:
- Verification of targets as military objectives (Art. 57(2)(a)(i)).
- Choice of means and methods of attack to minimize incidental civilian harm (Art. 57(2)(a)(ii)).
- Assessment of proportionality (Art. 57(2)(a)(iii)).
- Warnings when circumstances permit (Art. 57(2)(c)).
These obligations bind all parties to a conflict, regardless of whether they are parties to AP I, because the ICRC Customary IHL Database, Rule 15 identifies precautions as customary IHL applicable in both international and non-international armed conflicts (ICRC Customary IHL Database, Rule 15).
2.2 The authoritative interpretation
The International Court of Justice (ICJ) did not explicitly refer to Article 57 API or “precautions in attack” in its 1996 Nuclear Weapons Advisory Opinion. However, the Court reaffirmed the binding nature of the cardinal principles of international humanitarian law (IHL), which form the normative foundation for all precautionary duties. In paragraph 78 of the Opinion, the Court emphasized that civilian protection and distinction are among the core rules governing the conduct of hostilities:
“The first [cardinal principle] is aimed at the protection of the civilian population and civilian objects and establishes the distinction between combatants and non-combatants; States must never make civilians the object of attack and must consequently never use weapons that are incapable of distinguishing between civilian and military targets.”
3. Definitions and Scope
To understand the essence of Article 57 API, it is beneficial to recall the meaning of the following terms used in it:
Attack: An act of violence against the adversary, whether offensive or defensive (AP I, Art. 49).
Military objective: Objects which by their nature, location, purpose or use contribute effectively to military action, and whose destruction offers a definite military advantage (AP I, Art. 52(2)).
Feasible precautions: Measures that are practicable and possible in the circumstances, including operational, technological, informational, and procedural steps (ICRC Commentary).
Verification: Ensuring a target is not civilian in nature.
Warnings: Alerts to civilians of imminent attacks when military conditions permit.
This post focuses on how these definitions translate into practice.
4. Practical Application: How Armed Forces Implement Article 57 AP I
Precautions in attack play out across the entire targeting cycle, from the Commander´s intent to targeting assessment. Modern armed forces incorporate these rules through doctrine, training, data standards, and technology.
One of the most concrete, empirically grounded lines of work is the use of AI to detect civilians and protected objects in or near a target area and to highlight changes that could affect the lawfulness of an attack. A detailed 2022 CNA study on Leveraging AI to Mitigate Civilian Harm maps specific AI applications to real-world patterns of civilian harm observed in Afghanistan and Iraq. It identifies, among others, the following use cases:
4.1 United States (DoD)
The Civilian Harm Mitigation and Response Action Plan (CHMR-AP) (2022) institutionalizes precautionary measures by:
- establishing Civilian Harm Assessment Cells (CHACs) at combatant commands to improve incident analysis, post-strike assessment, and organizational learning.
- introducing new measures to improve intelligence accuracy and reduce target misidentification, including strengthened positive identification (PID) policies, expanded civilian-environment analysis, and enhanced sensor-driven battlespace awareness.
This directly implements Art. 57 duties: verification, feasible precautions in choice of means, and proportionality assessments.
4.2 United Kingdom
The UK implemented precautionary obligations through detailed doctrinal guidance in “The Joint Service Manual of the Law of Armed Conflict”, JSP 383. Chapter 5, section D (“Precautions in Attack”). It tracks Article 57 AP I and requires those who plan or decide upon attacks to:
- do everything feasible” to verify that objectives are genuine military objectives and not civilians or specially protected objects
- take all feasible precautions in the choice of means and methods of attack to avoid, or at least minimise, incidental loss of civilian life and damage to civilian objects
- refrain from launching attacks expected to cause excessive incidental civilian harm in relation to the concrete and direct military advantage anticipated.
- cancel or suspend attacks if it becomes apparent that the objective is not a military one or if the objective is subject to special protection; and
- give effective advance warning of attacks that may affect the civilian population, unless circumstances do not permit.
The Manual also codified “precautions against the effects of attacks” in line with Article 58 AP I, including obligations to remove civilians from the vicinity of military objectives, avoid locating military objectives in densely populated areas, and take other necessary measures (such as civil defence planning and evacuation) to protect civilians from the dangers of military operations.
4.3 Germany
- The Bundeswehr’s current LOAC regulation, “Zentrale Dienstvorschrift A-2141/1”, requires commanders to verify all targets using all information available at the time. They must ensure that the objective is a legitimate military objective and not a protected civilian person, object, or site (A-2141/1, no. 416, p. 48).s;
- Commanders must choose means and methods of attack that avoid or minimise incidental civilian harm. Attacks must be cancelled or suspended if proportionality cannot be maintained or if new information shows that the target is not a military objective (A-2141/1, no. 41, p. 48)
- If several military objectives offer similar military advantage, commanders must select the target likely to cause the least collateral damage (A-2141/1, no. 416, p. 48).
- When feasible, civilians must be removed from areas close to military objectives, and such objectives must not be located in or near densely populated areas (A-2141/1, no. 412, p. 47).
- The regulation stresses the obligation to provide effective advance warning of attacks that may affect civilians, unless circumstances do not permit (A-2141/1, no. 416, 48).
- Central Service Regulation A-2141/1 also imposes heightened duties for attacks against aircraft. These include using the best target-identification methods available—including but not limited to visual, electronic, and air-traffic data—and conducting careful assessments of expected collateral effects before attacks (A-2141/1, nos. 1153–1154, pp. 145).
4.4. NATO
NATO’s Allied Joint Doctrine for Joint Targeting embeds precautionary obligations in its core legal principles. In the section on proportionality, AJP-3.9 Section 1.6.2 d. requires that “all feasible precautions must be taken in the choice of means and methods of creating an effect, with a view to avoiding, or at least minimising, incidental loss of civilian life, injury to civilians and damage to civilian objects”, and that engagements be cancelled or suspended if the objective is not a military one or if excessive collateral damage is expected.
In its “other considerations” for targeting (Section 1.7) , the doctrine stresses heightened analysis of dual-use objects and presumes that objects normally dedicated to civilian purposes are not used for military action in cases of doubt.
AJP-3.9 Section 1.7. also includes a specific subsection on collateral damage considerations: commanders must decide whether expected collateral damage would be excessive and “must take all feasible precautions to avoid it,” supported by collateral damage estimation (CDE) tools that model proximity to civilians, weapon effects, and method or timing of engagement. This subsection emphasizes that CDE assists but does not replace the commander’s proportionality judgment.
5. Challenges in Contemporary Warfare
Modern conflicts create several obstacles for implementing feasible precautions:
5.1 Urban warfare
Urban fighting creates severe civilian risks, even when parties take precautions. The Report of the detailed findings of the independent commission of inquiry established pursuant to Human Rights Council resolution S-21/1 showed how civilians attempting to evacuate dense combat zones came under fire, illustrating the difficulty of distinguishing civilians from fighters in congested terrain (A/HRC/29/CRP.4, p. 124 et seq.)
5.2 Military Assets Embedded in Civilian Areas
The co-location of military and civilian functions complicates the application of precautions. The ICRC notes that infrastructure used by civilians is increasingly employed for military purposes, including “energy infrastructure, space systems and communication systems,” as well as roads, (air)ports, and transport systems (ICRC, Challenges of Contemporary Armed Conflicts, p. 40).
The report also highlights “overly permissive interpretations” of targeting rules and IHL as well as other “deliberate violations” of IHL that undermine civilian protection (pp. 37, and 7, 84) . These practices increase the complexity of verifying targets and assessing incidental harm in accordance with Article 57 AP I.
5.3 Fragmented Battlespaces and Interdependent Systems
Modern conflicts involve interconnected civilian systems where damage to one service can trigger cascading effects. The ICRC identifies electricity, water, health care, transport, and financial services as mutually dependent systems vulnerable to disruption during hostilities (ICRC, Challenges, p. 40)
Heavy explosive weapons are a primary cause of such wide-area effects. Urban fighting has produced “staggering numbers of civilian deaths” and long-term disruption of essential services (pp. 37–38). These dynamics require commanders to anticipate cross-domain consequences when applying the precautionary duties of Article 57.
If you have any questions, or would like to discuss particular aspects like engineering systems for Article 57 AP I compliance, auditing, dual-use infrastructure, or cyber defense applications, get in touch with me by email or just give me a call.