The use of force in international law
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# Types of armed conflict

Although generally only states can become a party to treaties, the rules of IHL must be respected by all parties to an armed conflict, irrespective of whether they are a state or non-state entity (e.g. a group of guerrilla fighters). However, the application of the correct legal framework depends primarily on the type of armed conflict. IHL distinguishes between two main types of conflict:

- international
- non-international (internal).

International armed conflict (IAC) involves fighting between armed forces of at least two states. The law applicable to international armed conflicts is enshrined in the Geneva Conventions I–IV and AP I.

In recent years non-international armed conflicts (NIAC) have become much more common. Such conflicts, civil wars, involve fighting between the regular armed forces of the state, on the one hand, and identifiable armed groups on the other; or else, fighting between two or more armed groups but with no state involvement.

## Box 4 Armed conflict(s) in Libya

Between February and October 2011, Libya was engaged in an armed conflict. When the Libyan Revolution broke out, Libya was in a state of an internal armed conflict: the fighting between pro-Gaddafi militias and the rebel armed groups (called thuwar) constituted NIAC.

Libya was also engaged in an IAC with the states participating militarily in the implementation of the measures authorised by UN Security Council Resolution 1973; this included the establishment of a no-fly zone over Libya.

Not all fighting within one country will be a civil war. There is a difference between internal disturbances, such as riots or protest against the state authorities, and NIAC. NIAC requires reaching of a certain threshold of intensity of general violence and it must extend over a certain period of time. The legal framework applicable to NIAC is much more limited than the framework applicable to IAC. It comprises Article 3 common to all four Geneva Conventions (Common Article 3) and the AP II.

## Box 5 Common Article 3 of the Geneva Conventions

Common Article 3 is often called ‘a treaty in miniature’ due to the number of rules it contains. It reads as follows:

> In the case of armed conflict not of an international character occurring in the territory of one of the High Contracting Parties, each Party to the conflict shall be bound to apply, as a minimum, the following provisions:

> 1. Persons taking no active part in the hostilities, including members of armed forces who have laid down their arms and those placed ‘hors de combat’ by sickness, wounds, detention, or any other cause, shall in all circumstances be treated humanely, without any adverse distinction founded on race, colour, religion or faith, sex, birth or wealth, or any other similar criteria.

>    To this end, the following acts are and shall remain prohibited at any time and in any place whatsoever with respect to the above-mentioned persons:

>    1. violence to life and person, in particular murder of all kinds, mutilation, cruel treatment and torture;
>    2. taking of hostages;
>    3. outrages upon personal dignity, in particular humiliating and degrading treatment;
>    4. the passing of sentences and the carrying out of executions without previous judgment pronounced by a regularly constituted court, affording all the judicial guarantees which are recognized as indispensable by civilized peoples.
> 2. The wounded and sick shall be collected and cared for.

>    An impartial humanitarian body, such as the International Committee of the Red Cross, may offer its services to the Parties to the conflict.

>    The Parties to the conflict should further endeavour to bring into force, by means of special agreements, all or part of the other provisions of the present Convention.

>    The application of the preceding provisions shall not affect the legal status of the Parties to the conflict.

The conduct of the protagonists in both NIAC and IAC is additionally regulated by the rules of customary international humanitarian law (CIHL). CIHL is of particular importance in modern armed conflicts. Generally, customary rules of IHL complement the rules enshrined in treaty law. As a result of the changing nature of warfare, treaty law is sometimes unable to adequately respond to the challenges posed by contemporary armed conflicts. As its rules derive from general state practice, CIHL fills in these gaps and so it strengthens the protection available to victims. Furthermore, customary rules are binding on all states, irrespective of whether the state ratified a treaty.

## Customary international humanitarian law and the ICRC

In 2005, the ICRC conducted a study on customary international humanitarian law. The study showed that rules regulating internal armed conflicts are much more extensive under CIHL than under treaty law. This is of particular significance, as the majority of modern armed conflicts are of a non-international character. Furthermore, as the treaty law regulating NIAC is rather limited, development of customary rules enhances protection of victims, but also those taking active part in hostilities.

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