"Laws are silent amidst the clash of arms." -  Cicero

In other words, war by its very nature is beyond the law. Wars break out when the rule of law breaks down, so there are no longer any rules.

The history of the law of international armed conflict shows that the field of application of this legal regime has been progressively extended as treaty law developed. Whereas a narrow formalistic concept of war was predominant initially, the reform of the system with the revision of the Geneva Conventions in 1949 gave precedence to a broader approach, based on the more objective concept of armed conflict.

Moreover, that extension was subsequently taken up with the adoption of Additional Protocol I in 1977. That instrument added another type of conflict to the field of the law of international armed conflict, that of wars of national liberation. This legal regime also comprises a specific body of rules whose field of application is determined based on an autonomous concept, that of occupation.

The States parties to the 1949 Geneva Conventions have entrusted the ICRC, through the Statutes of the International Red Cross and Red Crescent Movement, "to work for the understanding and dissemination of knowledge of international humanitarian law applicable in armed conflicts and to prepare any development thereof."[1]

It is on this basis that the ICRC takes this opportunity to present the prevailing legal opinion on the definition of "international armed conflict" and "non-international armed conflict" under International Humanitarian Law, the branch of international law which governs armed conflict.

International humanitarian law distinguishes two types of armed conflicts, namely:

• International armed conflicts, opposing two or more States, and
• Non-international armed conflicts, between governmental forces and nongovernmental armed groups, or between such groups only.

International Humanitarian treaty law also establishes a distinction between non-international armed conflicts in the meaning of common Article 3 of the Geneva Conventions of 1949 and non-international armed conflicts falling within the definition provided in Article 1 of Additional Protocol II.

Legally speaking, no other type of armed conflict exists. It is nevertheless important to underline that a situation can evolve from one type of armed conflict to another, depending on the facts prevailing at a certain moment.

International Armed Conflicts

The international armed conflict has been defined in Common Article 2 to the Geneva Conventions of 1949 which states that:
"In addition to the provisions which shall be implemented in peacetime, the present Convention shall apply to all cases of declared war or of any other armed conflict which may arise between two or more of the High Contracting Parties, even if the state of war is not recognized by one of them.

The Convention shall also apply to all cases of partial or total occupation of the territory of a High Contracting Party, even if the said occupation meets with no armed resistance."

According to this provision, IACs are those which oppose "High Contracting Parties", meaning States. An IAC occurs when one or more States have recourse to armed force against another State, regardless of the reasons or the intensity of this confrontation. Relevant rules of IHL may be applicable even in the absence of open hostilities.

The Commentary of the Geneva Conventions of 1949 confirms that "any difference arising between two States and leading to the intervention of armed forces is an armed conflict within the meaning of Article 2, even if one of the Parties denies the existence of a state of war. It makes no difference how long the conflict lasts, or how much slaughter takes place."[2]

Interpretation of term:
The International Criminal Tribunal for the former Yugoslavia (ICTY) proposed a general definition of international armed conflict. In the Tadic case, the Tribunal stated that:
"An armed conflict exists whenever there is a resort to armed force between States"[3]. This definition has been adopted by other international bodies since then.

According to D. Schindler:
"The existence of an armed conflict within the meaning of Article 2 common to the Geneva Conventions can always be assumed when parts of the armed forces of two States clash with each other. […] Any kind of use of arms between two States brings the Conventions into effect".[4]

H.P. Gasser explains that "any use of armed force by one State against the territory of another, triggers the applicability of the Geneva Conventions between the two States. […] It is also of no concern whether or not the party attacked resists. […] As soon as the armed forces of one State find themselves with wounded or surrendering members of the armed forces or civilians of another State on their hands, as soon as they detain prisoners or have actual control over a part of the territory of the enemy State, then they must comply with the relevant convention."[5]

Non-International Armed Conflict

Two main legal sources must be examined to determine what a Non-International Armed Conflict under international humanitarian law is:

• Common Article 3 to the Geneva Conventions of 1949 –
  Common Article 3 applies to "armed conflicts not of an international character occurring in the territory of one of the High Contracting Parties". These include armed conflicts in which one or more non-governmental armed groups are involved. Depending on the situation, hostilities may occur between governmental armed forces and non-governmental armed groups or between such groups only.
  
  As the four Geneva Conventions have universally been ratified now, the requirement that the armed conflict must occur "in the territory of one of the High Contracting Parties" has lost its importance in practice. Indeed, any armed conflict between governmental armed forces and armed groups or between such groups cannot but take place on the territory of one of the Parties to the Convention.
  
  To distinguish an armed conflict, in the meaning of common Article 3, from less serious forms of violence, such as internal disturbances and tensions, riots, or acts of banditry, the situation must reach a certain threshold of confrontation. It has been generally accepted that the lower threshold found in Article 1(2) of Additional Protocol II, which excludes internal disturbances and tensions from the definition of Non-International Armed Conflict, also applies to common Article 3.
  
  Two criteria are usually used in this regard[6]:
  
  • First, the hostilities must reach a minimum level of intensity. This may be the case, for example, when the hostilities are collective or when the government is obliged to use military force against the insurgents, instead of mere police forces.[7]
     
  • Second, non-governmental groups involved in the conflict must be considered as "parties to the conflict", meaning that they possess organized armed forces. This means for example that these forces have to be under a certain command structure and have the capacity to sustain military operations.[8]
  
   
• Article 1 of Additional Protocol II:
  A more restrictive definition of Non-International Armed Conflict was adopted for the specific purpose of Additional Protocol II. This instrument applies to armed conflicts "which take place in the territory of a High Contracting Party between its armed forces and dissident armed forces or other organized armed groups which, under responsible command, exercise such control over a part of its territory as to enable them to carry out sustained and concerted military operations and to implement this Protocol."[9]
   

This definition is narrower than the notion of Non-International Armed Conflict under common Article 3 in two aspects.

• Firstly, it introduces a requirement of territorial control, by providing that non-governmental parties must exercise such territorial control "as to enable them to carry out sustained and concerted military operations and to implement this Protocol".
   
• Secondly, Additional Protocol II expressly applies only to armed conflicts between State armed forces and dissident armed forces or other organized armed groups. Contrary to common Article 3, the Protocol does not apply to armed conflicts occurring only between non-State armed groups.

In this context, it must be reminded that Additional Protocol II "develops and supplements" common Article 3 "without modifying its existing conditions of application."[10] This means that this restrictive definition is relevant for the application of Protocol II only, but does not extend to the law of NIAC in general. The Statute of the International Criminal Court in its article 8, paragraph 2 (f), confirms the existence of a definition of a non-international armed conflict not fulfilling the criteria of Protocol II.[11]

Interpretation of the term:
Case law has brought important elements for a definition of an armed conflict, in particular regarding the non-international armed conflicts in the meanings of common Article 3 which are not expressly defined in the Conventions concerned.

Several recognized authors also commented very clearly on what should be considered as a non-international armed conflict. Their comments are relevant in the first place to the conflicts which do not fulfill the strict criteria foreseen in Additional Protocol II and provide useful elements to ensure the application of the guarantees provided in common article 3 to the Geneva Conventions of 1949.

According to H.P. Gasser, it is generally admitted that:
"Non-international armed conflicts are armed confrontations that take place within the territory of a State between the governments on the one hand and armed insurgent groups on the other hand. […] Another case is the crumbling of all government authority in the country, as a result of which various groups fight each other in the power struggle."[12]

D. Schindler also proposes a detailed definition:
"The hostilities have to be conducted by a force of arms and exhibit such intensity that, as a rule, the government is compelled to employ its armed forces against the insurgents instead of mere police forces. Secondly, as to the insurgents, the hostilities are meant to be collective, [i.e] they have to be carried out not only by single groups. Besides, the insurgents have to exhibit a minimum amount of organization. Their armed forces should be under a responsible command and be capable of meeting minimal humanitarian requirements."[13]

Additionally, Articles 1 and 7 of the Statute of the International Criminal Tribunal for Rwanda extend the jurisdiction of that tribunal called to enforce, inter alia, the law of non-international armed conflicts, to the neighboring countries. This confirms that even a conflict spreading across borders remains a non-international armed conflict. In conclusion, 'internal conflicts are distinguished from international armed conflicts by the parties involved rather than by the territorial scope of the conflict.'[14]

Application of International law in matters concerning Non-International Armed Conflict

In a non-international armed conflict, each party is bound to apply, as a minimum, the fundamental humanitarian provisions of international law contained in Article 3 common to all four Geneva Conventions. Those provisions are developed in and supplemented by Geneva Protocol II of 1977.

Both common Article 3 and Geneva Protocol II apply with equal force to all parties to an armed conflict, government and rebels alike. Besides, government troops and rebel forces must apply several other specific treaty rules relating to internal conflicts, namely:

• Article 19 of the 1954 Cultural Property Convention and its Second Protocol of 1999 (the latter protocol has not yet entered into force at the time of writing);
• Protocol II to the Conventional Weapons Convention, on Prohibitions or Restrictions on the Use of Mines, Booby-Traps and Other Devices, as amended on 3 May 1996;
• The Ottawa landmines treaty of 1997.
• The rules of customary international law certainly apply as well, in particular the basic principles of the law of armed conflict we covered in detail in earlier lessons, namely distinction, proportionality, military necessity, limitation, good faith, and humane treatment.

Conclusion
In simple words, the conclusion of the definitions can be drawn as:

• International armed conflicts exist whenever there is a resort to armed force between two or more States.
• Non-international armed conflicts are protracted armed confrontations occurring between governmental armed forces and the forces of one or more armed groups, or between such groups arising on the territory of a State [party to the Geneva Conventions]. The armed confrontation must reach a minimum level of intensity and the parties involved in the conflict must show a minimum of organization.

Apart from the definitions of both the conflicts, interpretation, and understanding are also required to be kept in mind while dealing with the issues.

Resources

• https://www.icrc.org/en/doc/assets/files/other/law1_final.pdf
• https://www.icrc.org/en/doc/assets/files/other/law10_final.pdf
• https://www.icrc.org/en/doc/assets/files/other/opinion-paper-armed-conflict.pdf

End-Notes:

1. Statutes of the International Red Cross and Red Crescent Movement, art. 5, para. 2(g)
2. J. Pictet, Commentary on the Geneva Convention for the Amelioration of the Condition of the Wounded and Sick in Armed Forces in the Field, ICRC, Geneva, 1952, p. 32
3. ICTY, The Prosecutor v. Dusko Tadic, Decision on the Defence Motion for Interlocutory Appeal on Jurisdiction, IT-94-1-A, 2 October 1995, para. 70
4. D. Schindler, The different Types of Armed Conflicts According to the Geneva Conventions and Protocols, RCADI, Vol. 163, 1979-II, p. 131.
5. H.P. Gasser, International Humanitarian Law: an Introduction, in Humanity for All: the International Red Cross and Red Crescent Movement, H. Haug (ed.), Paul Haupt Publishers, Berne, 1993, p. 510- 511.
6. ICTY, The Prosecutor v. Dusko Tadic, Judgment, IT-94-1-T, 7 May 1997, para. 561-568; see also ICTY, The Prosecutor v. Fatmir Limaj, Judgment, IT-03-66-T, 30 November 2005, para. 84
7. For a detailed analysis of this criteria, see ICTY, The Prosecutor v. Fatmir Limaj, Judgment, IT-03- 66-T, 30 November 2005, para. 135-170
8. See D. Schindler, The Different Types of Armed Conflicts According to the Geneva Conventions and Protocols, RCADI, Vol. 163, 1979-II, p. 147. For a detailed analysis of this criteria, see ICTY, The Prosecutor v. Fatmir Limaj, Judgment, IT-03-66-T, 30 November 2005, para. 94-134
9. Additional Protocol II, art. 1, para. 1
10. ibid
11. Statute of the ICC, art. 8 para. 2 (f): "It applies to armed conflicts that take place in the territory of a State when there is a protracted armed conflict between governmental authorities and organized armed groups or between such groups"
12. H.P. Gasser, International Humanitarian Law: an Introduction, in Humanity for All: the International Red Cross and Red Crescent Movement, H. Haug (ed.), Paul Haupt Publishers, Berne, 1993, p. 555.
13. D. Schindler, The Different Types of Armed Conflicts According to the Geneva Conventions and Protocols, RCADI, Vol. 163, 1979-II, p. 147
14. Liesbeth Zegveld, Accountability of Armed Opposition Groups in International Law, Cambridge: Cambridge University Press, 2002, p. 136