Exploring the Relationship Between Modern International Law and Warfare

By Alexandra Crow

It has been argued by scholars such as David Kennedy that modern warfare is a legal institution. Kennedy argues that "when we talk about war today... we are not talking about wars between great powers, relatively equal in size... war today tends to happen at the periphery of the system among extremely unequal players." He goes on to state that this modern warfare takes place with the involvement of non-state actors and new warfare technologies. He argues on this basis that the changing nature of the relationship between law and war means that law ends up legitimising the use of force rather than restricting it. Law legitimises certain actions in war such as whether a particular strike was proportionate, and this takes the discussion out of the old moral justifications and into a legal realm. He argues that this ends up causing more conflict and violence.

In an attempt to understand the arguments of critics of international law such as Kennedy, it is useful to look at a few of the key international legal instruments governing the use of force and armed conflict. It’s difficult to know where to begin with public international law because it is so vast in the sources it draws from. However, having a good understanding of the more commonly referred to instruments, especially those regulating armed conflict and the use of force, is a good start.  

The signing of the Geneva Convention 1864.

The first significant inter-state agreement aimed at restraining the undesirable effects of armed conflict was the Geneva Convention 1864. This was significant in that it was signed by 12 European states and gained its obligatory force from the consent of the states which accepted and applied them in the conduct of their military operations. The Convention was successful in effecting significant and rapid reforms to improve the treatment of wounded and sick armed forces in the field.  The four treaties that make up the Geneva Conventions constitute a body of humanitarian law covering the treatment and protection of civilians and other non-combatants.

Further regulations concerning armed conflict, and also the use of force, are set out in the Hague Conventions 1899 and 1907. These were the first set of conventions to lay down formal principles concerning disarmament, war crimes and restricting certain methods of warfare such as the use of projectiles by balloons. It also set up the Permanent Court of Arbitration with the intention of settling disputes before resorting to war. Although not all the great powers ratified or formally accepted these declarations, they are now generally accepted to comprise part of customary law.

So this was effectively the codification, in one legally binding instrument, of international law as it related to armed conflict and the use of force. However it was not exhaustive in the situations it covered. So it was established in a principle called the Martens Clause that where the law was silent, customary law would continue to govern. It is contained in the preamble of the Hague Convention 1899. This principle has been more widely interpreted in the application of modern international law providing that an act which is not explicitly prohibited by a treaty does not mean that that act is automatically permitted, thus expanding the scope of international law is warfare.

The United Nations General Assembly.

The Charter of the United Nations 1945 which established the United Nations, is arguably the most important modern document of international law. The Charter is based around restricting the possibility of further war with the first line stating the purpose is “to save succeeding generations from the scourge of war, which twice in our lifetime has brought untold sorrow to mankind.” This has been described as a major shift towards multilateral institutions, whereby numerous states come together and work on various issues, prompted perhaps by the increasingly connected nature of our globalised world. David Kennedy makes a point in his book that due to these developments "states can no longer expect to be sovereign in the way that they previously were"; he then relates this to war sating that "all governments have less focused power to decide for war and peace than they had a century ago."

Click here to view the enlarged version of the diagram. 

The most significant provision in the UN Charter relating to modern warfare is the complete prohibition on the threat or use of force set out in Article 2(4). Chapter 7 of the Charter states that force may only be used when authorised by the UN Security Council. This approach is intended to remove subjective judgments by powerful states about when it is acceptable to use force. There are various options that can be considered and tried before the UN Security Council will authorise the use of force. These include the use of sanctions on economic relations, arms embargos, flight bans, the severance of diplomatic relations, among other things. 

A Palestinian woman sits on the rubble of her home on July 26, 2014.

The notable exception to the prohibition on the use of force is the right to self-defence set out in Article 51 of the Charter. There are two requirements that have to be met in order to use force in self-defence: the action taken must be necessary and it must be proportionate to the threat. Customary law states that the requirement for necessity can only be met if the threat is imminent but it is now also recognised that there is an anticipatory dimension, due to the nature of modern weapons technology and to deal with the issue of modern terrorism. This is often the justification used by states to perform acts of violence such as the US invasion of Afghanistan in 2001 and Iraq in 2003 and the 2008 attack on Gaza by Israel referred to in the readings. 

Finally, we conclude with a discussion of the rules surrounding armed conflict which is regulated by the body of law known as international humanitarian law. This is predominantly found in customary law and is a series of principles that are binding on states through Article 38(1)(c) of the Statute of the International Court of Justice. There are several important principles that make up this body of law. For example the principle of distinction, that is the idea that there must be a distinction between combatants and non-combatants. Article 48 of Protocol 1 Additional to the Geneva Conventions 1977 states that civilians must not be the object of attack. This is meant to provide an overarching prohibition on the targeting of civilians in warfare. Another example of these principles is the prohibition on the use of indiscriminate weapons. This carries on from the first rule requiring states to never use weapons that are incapable of distinguishing between civilian and military targets. This would perhaps rule out all use of nuclear weapons, expect in an extreme circumstance of self-defence.

So when considering that the sources mentioned above are only a minute part of international law we can perhaps understand why Kennedy describes international law as a “fragmented and unsystematic network of institutions…. which are only loosely understood or coordinated by national governments”. The intention of international law however is to restrict the use of force and to constrain and regulate armed conflict. There are many reasons to be sceptical of the effectiveness of international law however there have been examples of super powers being held to account for excessive force by international law such as the Nicaragua v United States of America case heard in the International Court of Justice. So it is arguable that, for all its faults, it is better to have a system of international law that attempts, and sometimes succeeds, in restricting states' use of force, than not have one at all. Hopefully this brief introduction to international law will help in assessing the value of the arguments of critics such as Kennedy.

To listen to a more in-depth discussion of David Kennedy's arguments, check out the video below.