Concept and Function of International Humanitarian Law
International humanitarian law is the branch of public international law that regulates the conduct of parties during armed conflict. It protects persons who do not, or no longer, take part in hostilities and restricts the means and methods of warfare. Its object is not to decide who is right in the conflict, but to preserve minimum standards of humanity once armed violence has reached the legal threshold of an armed conflict.
IHL is also called the law of armed conflict. It is part of the law of war, but it is distinct from the rules on the legality of resorting to force. The legality of the decision to use force belongs to jus ad bellum; the legality of conduct during the fighting belongs to jus in bello. IHL applies equally to all parties to an armed conflict, regardless of who began the hostilities, whose cause is lawful, or whether one party is a State and the other is an organized armed group.
The equal application of IHL prevents a party from denying humanitarian protections by calling the adversary criminal, rebellious, terrorist, or illegitimate. In a non-international armed conflict, the State may still prosecute insurgency, rebellion, terrorism, murder, illegal possession of firearms, and other domestic offenses, but it must conduct operations, detention, and trial consistently with humanitarian obligations and fundamental judicial guarantees.
Under the Philippine constitutional system, generally accepted principles of international law form part of the law of the land, and the Philippines renounces war as an instrument of national policy. Treaty obligations, customary IHL, domestic implementing laws, military regulations, and ordinary criminal law operate together. State forces remain bound by the Constitution and human rights norms, while organized armed groups are bound by IHL when they are parties to an armed conflict.
When IHL Applies
IHL applies only when an armed conflict exists. Ordinary criminality, riots, isolated clashes, political demonstrations, and internal tensions do not by themselves trigger IHL. When the violence is below the armed conflict threshold, the governing framework is domestic law, constitutional rights, human rights law, and law enforcement standards on necessity, legality, accountability, and proportionality in the police sense.
A formal declaration of war is unnecessary. The actual facts determine whether an armed conflict exists. The controlling considerations are the identity of the parties, the intensity of the violence, and, for non-State groups, their degree of organization. Labels used by the parties are relevant only as evidence; they do not control the legal classification.
| Situation | Basic Legal Character | Main IHL Consequence |
|---|---|---|
| International armed conflict | Armed force between States, including occupation even without active resistance | Full treaty and customary rules on combatants, prisoners of war, civilians, occupation, and conduct of hostilities apply |
| Non-international armed conflict | Protracted armed violence between State forces and organized armed groups, or between such groups | Common humanitarian guarantees, customary rules, and applicable treaty rules bind all parties |
| Internal disturbance | Violence below the required intensity or organization threshold | IHL does not apply, but human rights law, criminal law, and law enforcement rules remain controlling |
For Philippine internal security operations, the legal characterization matters because many confrontations involve State forces and non-State armed groups. If the intensity and organization thresholds are met, IHL governs the conduct of hostilities in addition to domestic law. If the threshold is not met, force must be assessed under law enforcement standards rather than targeting rules for armed conflict.
Relationship with Human Rights Law and Domestic Law
IHL and human rights law may apply at the same time. Human rights law continues during armed conflict, subject to lawful derogations where permitted and subject always to non-derogable rights. IHL supplies the more specific rule for conduct of hostilities, detention linked to armed conflict, treatment of the wounded, and protection of civilians in areas affected by fighting.
The right to life illustrates the relationship. In ordinary law enforcement, intentional lethal force is allowed only when strictly necessary to protect life or prevent similarly grave harm. In armed conflict, lethal force may be directed at combatants in an international conflict and at persons who are targetable under IHL in a non-international conflict, subject to distinction, proportionality, and precautions. Even in armed conflict, murder, summary execution, torture, enforced disappearance, and deliberate attacks on civilians remain unlawful.
Domestic law does not disappear when IHL applies. Philippine criminal law, special penal statutes, rules of evidence, court jurisdiction, administrative discipline, and remedies for rights violations remain relevant. IHL may affect the legal analysis of a use of force, detention, or destruction of property, but it does not create a general license to disregard constitutional guarantees or ordinary accountability mechanisms.
Protected Persons
The central protective idea of IHL is that persons who are not fighting must be spared, and persons who have stopped fighting must be treated humanely. The protection is functional rather than sentimental: it maintains the distinction between lawful military operations and violence against the defenseless.
- Civilians are protected against attack unless and for such time as they directly participate in hostilities.
- Wounded, sick, and shipwrecked persons must be respected, protected, collected, and cared for without adverse distinction.
- Persons deprived of liberty must be treated humanely and protected from torture, cruel treatment, outrages upon dignity, and sentencing without fundamental judicial guarantees.
- Medical and religious personnel must be respected and protected while performing their humanitarian functions.
- Humanitarian relief personnel performing impartial humanitarian work must be protected, subject to lawful control measures of the parties.
- Children receive special respect and protection, including protection against recruitment and use in hostilities.
- Women and persons exposed to sexual violence are protected by the general rules on humane treatment and by specific prohibitions against rape, sexual slavery, enforced prostitution, forced pregnancy, enforced sterilization, and other forms of sexual violence.
- Journalists engaged in dangerous professional missions are civilians so long as they do not take a direct part in hostilities.
In international armed conflict, combatants are members of the armed forces of a party, except medical and religious personnel. Combatants may be directly attacked while they remain combatants, but they are entitled to prisoner-of-war status upon capture if they meet the applicable conditions. Prisoner-of-war status is an international armed conflict concept and includes immunity from prosecution merely for lawful acts of war, although it does not protect war crimes.
In non-international armed conflict, there is no general combatant privilege and no prisoner-of-war status as such. Members of organized armed groups may be targetable based on their continuous combat function, and civilians may be targetable for the duration of direct participation in hostilities. Capture does not erase criminal liability under domestic law, but it requires humane treatment and fair trial guarantees.
Protected Objects and Places
IHL protects civilian objects, medical units, religious sites, cultural property, schools, indispensable objects for civilian survival, and humanitarian relief consignments. A civilian object is any object that is not a military objective. Doubt should be resolved in favor of civilian character when the object is ordinarily dedicated to civilian use.
A military objective is limited to an object which, by its nature, location, purpose, or use, makes an effective contribution to military action and whose total or partial destruction, capture, or neutralization offers a definite military advantage in the circumstances ruling at the time. This definition prevents attacks based on vague strategic value, collective punishment, economic hostility, or speculation.
Objects indispensable to civilian survival, such as food supplies, drinking water installations, crops, livestock, and irrigation works, cannot be attacked, destroyed, removed, or rendered useless for the purpose of starving civilians. Starvation of civilians as a method of warfare is prohibited. Humanitarian relief must not be arbitrarily impeded when the civilian population lacks supplies essential for survival, although parties may impose lawful controls to verify the humanitarian and impartial character of relief operations.
Medical units and transports lose protection only if they are used, outside their humanitarian function, to commit acts harmful to the enemy, and ordinarily only after due warning remains unheeded. The protective emblems associated with medical services must not be misused. Misuse of the emblem weakens the protection of the wounded and medical personnel and may amount to a serious violation when connected to hostilities.
Basic Principles Governing Hostilities
The conduct of hostilities is governed by a set of interlocking principles. No principle operates in isolation. Military necessity permits only measures necessary to achieve a legitimate military purpose and not otherwise prohibited by IHL. Humanity forbids unnecessary suffering and the destruction of life or property not required by legitimate military necessity.
| Principle | Operational Rule | Legal Effect |
|---|---|---|
| Distinction | Parties must distinguish civilians from fighters and civilian objects from military objectives | Only military objectives and targetable persons may be attacked |
| Proportionality | Incidental civilian harm must not be excessive in relation to the concrete and direct military advantage anticipated | An attack may be unlawful even if the target is military |
| Precautions | Feasible precautions must be taken in choosing targets, weapons, timing, warnings, and methods | Parties must reduce incidental civilian harm as far as practicable |
| Humanity | Persons under control of a party must be treated humanely | Torture, cruel treatment, humiliating treatment, and summary execution are prohibited |
| Unnecessary suffering | Weapons and methods must not cause superfluous injury or unnecessary suffering | Some weapons or uses are unlawful regardless of military usefulness |
Distinction is the first discipline of targeting. Deliberate attacks on civilians or civilian objects are prohibited. Indiscriminate attacks are also prohibited. An attack is indiscriminate when it is not directed at a specific military objective, uses means or methods that cannot be directed at such an objective, or uses means or methods whose effects cannot be limited as required by IHL.
Proportionality does not compare the value of enemy lives and friendly lives. It compares expected incidental civilian death, injury, and damage with the concrete and direct military advantage anticipated from the attack. The anticipated advantage must be military, direct, and concrete, not political, psychological, retaliatory, or speculative.
Precautions require commanders and fighters to verify targets, choose means and methods that reduce civilian harm, give effective advance warning when circumstances permit, and cancel or suspend an attack if it becomes apparent that the target is not military or that incidental harm would be excessive. Feasible precautions are those practicable or practically possible in the circumstances, considering humanitarian and military considerations.
Prohibited Methods of Warfare
IHL prohibits methods of warfare that attack the humanitarian structure of the law itself. These prohibitions apply because some methods are incompatible with distinction, humane treatment, or the protection of persons under control of a party.
- Perfidy consists of inviting the confidence of an adversary to believe that protection under IHL applies, with intent to betray that confidence, such as feigning surrender in order to kill.
- Denial of quarter means declaring or conducting hostilities on the basis that no survivors will be left, which negates the duty to spare persons who surrender or are hors de combat.
- Human shields are civilians or other protected persons used to render military objectives immune from attack or to impede military operations.
- Starvation of civilians as a method of warfare is prohibited, including attacks on objects indispensable to civilian survival when done for that purpose.
- Collective punishment punishes persons or communities for acts they did not individually commit and is incompatible with personal responsibility.
- Pillage is the appropriation of property for private or personal use in connection with hostilities and is prohibited in both international and non-international armed conflicts.
- Hostage-taking uses a detained or controlled person to compel action or inaction by another party and is a grave violation of humane treatment.
- Forced displacement of civilians is prohibited unless required for the security of the civilians involved or for imperative military reasons.
Ruses of war are not the same as perfidy. Camouflage, decoys, mock operations, misinformation directed at the enemy's military assessment, and surprise tactics may be lawful if they do not abuse a protected status or emblem and do not invite reliance on IHL protection.
Means of Warfare and Weapons
The right of parties to choose weapons is not unlimited. A weapon or its manner of use is unlawful if it is by nature indiscriminate, causes superfluous injury or unnecessary suffering, or is prohibited by a treaty or customary rule applicable to the parties. A weapon that can be lawful in one context may be used unlawfully if employed against civilians, in a civilian area without feasible precautions, or in a way expected to cause excessive incidental harm.
The assessment of weapons has both an abstract and concrete dimension. Abstract review asks whether the weapon is inherently unlawful. Concrete review asks whether the actual use of the weapon in the circumstances complies with distinction, proportionality, and precautions. In densely populated areas, the concrete review becomes especially important because even a weapon not unlawful by nature may cause foreseeable civilian harm that makes a particular attack unlawful.
Explosive weapons, aerial attacks, artillery, cyber operations, and other modern methods must be assessed under ordinary IHL principles. The legal question is not whether the technology is new, but whether the operation identifies a military objective, avoids indiscriminate effects, limits incidental civilian harm, and respects protected persons and objects.
Humane Treatment and Detention
All persons in the power of a party to the conflict must be treated humanely. The minimum guarantees prohibit violence to life and person, murder, mutilation, cruel treatment, torture, hostage-taking, outrages upon personal dignity, and passing sentences or carrying out executions without judgment by a regularly constituted court that affords essential judicial guarantees.
Humane treatment applies without adverse distinction based on race, color, religion, sex, birth, wealth, political opinion, or similar criteria. It applies to captured fighters, civilians, suspected members of armed groups, informants, wounded persons, and detainees accused of grave crimes. The seriousness of the accusation does not reduce the duty to treat the person humanely.
Interrogation must not involve torture, cruel treatment, threats, sexual violence, enforced disappearance, or coercion that violates law. Medical care must be based on need, not allegiance. Dead bodies must be respected, searched for, collected when feasible, identified as far as possible, and protected from despoliation and degrading treatment.
In the Philippine setting, detention connected with armed conflict must also be examined under constitutional safeguards, criminal procedure, statutory rights of persons arrested or detained, prohibitions on torture and enforced disappearance, and the jurisdiction of courts and accountability bodies. IHL does not create a zone outside the Constitution.
Special Protection of Children and Other Vulnerable Persons
Children affected by armed conflict are entitled to special respect and protection because their age increases their vulnerability to recruitment, displacement, separation, trauma, sexual violence, and exploitation. Philippine law specifically protects children in situations of armed conflict and treats recruitment, use, killing, maiming, rape, abduction, attacks on schools or hospitals, and denial of humanitarian access as grave concerns.
The recruitment and use of children in hostilities violates IHL and domestic law. The protection is not limited to direct fighting. Children may be unlawfully used as couriers, guides, spies, guards, porters, messengers, or in other roles that expose them to the dangers of hostilities or integrate them into armed operations.
Women, older persons, persons with disabilities, internally displaced persons, indigenous communities, and persons deprived of liberty may require specific measures of protection without losing the benefit of general IHL rules. Protection against sexual violence is not merely a matter of dignity; depending on context, it may constitute a war crime, a crime against humanity, torture, or an act contributing to genocide.
Accountability and Philippine Implementation
IHL is enforced through prevention, discipline, investigation, prosecution, reparative measures, and international responsibility. States must train armed forces, issue operational instructions, suppress violations, and investigate credible allegations. Commanders must plan and supervise operations with IHL in view, not treat humanitarian rules as post-operation justifications.
Philippine law punishes war crimes, genocide, and other crimes against humanity through domestic legislation. The statutory framework recognizes that serious violations may be committed by State agents, members of organized armed groups, private individuals, superiors, or subordinates. Official position does not by itself exempt a person from criminal responsibility for international crimes.
Command or superior responsibility attaches when a superior has effective command and control, or effective authority and control, over subordinates; knew or had reason to know that they were committing or about to commit crimes; and failed to take necessary and reasonable measures to prevent, repress, or submit the matter for investigation and prosecution. The doctrine is based on responsible control, not automatic liability for rank.
War crimes require a nexus to armed conflict. Genocide requires a specific intent to destroy, in whole or in part, a protected group as such. Crimes against humanity require a widespread or systematic attack directed against a civilian population, with knowledge of the attack, and do not require the existence of an armed conflict. These categories may overlap factually, but each has a distinct legal focus.
Amnesty may be encouraged after a non-international armed conflict for mere participation in hostilities or political offenses, but it cannot validly erase responsibility for genocide, crimes against humanity, war crimes, torture, enforced disappearance, and other serious violations that international law requires States to investigate and punish.
International Criminal Court and Complementarity
The International Criminal Court is a permanent treaty-based court that prosecutes individuals for the most serious international crimes when national systems are unwilling or unable genuinely to investigate or prosecute. Its jurisdiction is complementary to domestic jurisdiction. The first responsibility to investigate and prosecute international crimes remains with national authorities.
For the Philippines, the ICC must be understood together with domestic accountability. Philippine courts and prosecutors remain the ordinary forum for crimes committed in Philippine territory or by persons subject to Philippine jurisdiction. The existence of the ICC does not remove the duty of domestic institutions to investigate serious violations of IHL.
The Philippines withdrew from the Rome Statute effective in 2019. Withdrawal does not erase possible jurisdiction over crimes allegedly committed while the State was a party, and it does not cancel duties that had already arisen in relation to proceedings commenced before withdrawal. For present domestic analysis, however, Philippine legislation on international crimes remains independently significant even apart from ICC membership.
Operational Consequences
IHL affects decisions at every level of armed conflict. Strategic policy must identify applicable legal frameworks. Command planning must integrate target verification, civilian risk assessment, detention procedures, medical evacuation, reporting, and investigation. Field operations must translate legal rules into orders that fighters can follow under pressure.
A lawful military operation requires more than a legitimate enemy objective. It requires a targetable person or military objective, lawful means, proportional incidental harm, feasible precautions, humane treatment of persons in control, respect for medical and humanitarian functions, and accountability for violations. A violation by one party does not release the other party from IHL obligations.
The controlling idea is disciplined humanity within armed conflict. IHL accepts that armed conflict involves force, destruction, detention, and death, but it rejects cruelty, terror, lawlessness, and violence against those who are not legitimate objects of attack. In Philippine law, that discipline is reinforced by the Constitution, domestic criminal statutes, human rights obligations, and the continuing jurisdiction of courts over serious violations.