Revising the Laws of War: The case of Preemption

Posted on Posted in Analyses, Strategy & Defence

By Alexandra Alexandridou, Analyst KEDISA

Should international law be continuously revised and updated, so as to abide by the new circumstances in particular in the case of war? And what about the potential legalization of preemptive self-defense? The answers to these questions can be found in the perpetual change on the international scene. As relations between international actors evolve, as their interests change and as technology advances, enabling the creation of Weapons of Mass Destruction (WMDs), new challenges arise in the international environment, obliging international law to adapt in order to control these newly emerging interrelations.
Let us begin by examining the process through which international laws are revised. Modifications in a law come about when an actor unilaterally changes its interpretation of that law either in practice or explicitly. The other states respond to this modification through diplomacy and the new practice acquires legitimacy either as customary law or by means of a prescribed form which has more power. Given that the establishment of laws serves only as a means to vouchsafe international security, their reformulation upon new circumstances is legitimate.
Having clarified the process of law change and having established that it is a blessing for the international community rather than a curse, let us trace back the laws of war and see how they were being modified depending on the variables of each era. The “jus ad bellum”, the law referring to war in the 20th century prohibited the use of proactive military force and permitted only the use of reactive one, as a means of self-defense. The use of force should of course be necessary, proportional to the attack, which should be armed and of a significant scale, and discriminating.
As weapons became more destructive, however, anticipatory self-defense started also being considered permissible as a means to avoid the repercussions of potential attacks. In the case of anticipatory self-defense, the use of force is directed to a threat of a possible future attack, not to an actual attack, so there always lurks the danger of abusing the term, as it happened in the Nicaragua case of 1984 on the part of the United States. Entering the nuclear era we came upon equilibrium in the nuclear capacity of the two superpowers of the time, the US and the Soviet Union, which using deterrence practices against each other maintained the world order and prevented global wars. During the Cold War, the creation of Anti-Ballistic Missile (ABM) systems was proposed as protection to the potential use of the nuclear weapons by one of the superpowers, but the employment of ABMs was rejected by the ABM Treaty signed in 1972, since their employment constituted a form of anticipatory self-defense. As, however, more countries started accumulating nuclear weapons, the ABM Treaty was denounced by the Bush administration and ABM systems were ultimately considered as an effective response to the nuclear arsenals of smaller states.
Up to that point, the law of war applied only to states but to no non-state actors in the international environment. After the terrorist attacks of 9/11 it was amplified to apply to the cases of terrorist organizations as well, so the fight against terrorism was gradually identified with the notion of preemptive self-defense. Preemption does not refer to the armed response to an actual attack as in reactive self-defense, nor to a preventive response to an imminent threat of an attack, as in anticipatory self-defense. It rather aims at preventing a contingent threat of a possible attack. In this case, not only is the attack not imminent, but perhaps not even the threat. The United States used successfully the threat of preemption, not actual preemption, far before the terrorist attacks of 9/11, during the Clinton administration against Iraq and North Korea. It was not until the Bush administration, however, that it declared openly its disposition to use preemptive means even unilaterally in order to prevent the terrorists’ acquisition of WMDs and their reaching the United States.
Here lies the question of the legitimacy of preemptive self-defense, which is not a new phenomenon in international politics. In the case of the Six-Days War the attack on the part of Israel against Egypt without any actual provocation from the latter, was not condemned internationally, since Egypt and Israel were considered to find themselves in a belligerent condition, so any initiation of hostilities was anticipated. The same could be claimed in the case of the United States against the Al Qaeda, in that they were too in a war-like condition, so the acts on the part of the US are not considered preemptive. It thus becomes clear that the lawfulness of each self-defense action is in practice judged ex post facto according to the context, making difficult an a priori establishment of rules. Nonetheless, it should always be judged against certain criteria, such as the degree of the threat, the collective international response to the issue, the urgency of unilateral action and the proportionality of the means deployed given the threat.
Various issues arise regarding the legitimacy of preemptive self-defense. First of all, it entails the same degree of danger of abuse and misinterpretation as anticipatory self-defense. In this respect, it imposes no extra burdens on the international community regarding law violation compared to the ones imposed by preventive self-defense. Besides, humanitarian missions intervene in a country without any prior threat too, in that sense they violate the law of no intervention in foreign affairs, albeit in order to maintain peace and order. Nevertheless, the formal legalization of preemptive self-defense implies the risk of augmentation of violence and wars. On the other hand, the alternative would be that countries endured mild conflicts and did not take action in order to avoid armed incidents.
Those are crucial questions which have to be answered before passing a definite judgment on the legitimacy of preemption. Yet in order to assess the introduction of any new laws, one should consider whether they will benefit all actors involved in present and future contexts. For example, the creation of ABM systems is deemed purely defensive and does not hurt other countries. Intervention in order to inflict a regime change, however, would imply further legitimation of one country’s interference in another country’s affairs besides lawful humanitarian intervention.
The reality regarding preemptive self-defense as it stands nowadays renders preemption an American doctrine. A doctrine is the interface between a law and power and expresses the will of a significant international actor to implement a policy upon certain cases, exactly as it happened with the Bush declarations after 9/11. Even though it constitutes an exception to the rule, it serves at maintaining the world order because all other actors are aware of the consequences their actions might bring about. This way, international laws are constantly abused primarily by the most powerful states, in defense of their national interests and national security, whereas global security is considered of secondary importance. International matters, however, should be dealt with collectively by the international community, not unilaterally by a few powerful states.
Self-defense laws, therefore, should always adapt according to the status quo of each era, taking into consideration the principles of necessity, proportionality and discrimination, so that they provide viable action frameworks to individual states and do not render their choices illegal. As for the legitimization of preemption, international policy-makers should first find feasible solutions to the challenges mentioned above, before reaching a conclusion on a matter that directly affects the national security of each state.


Ari Fleischer, ABM Treaty Fact Sheet: Announcement of Withdrawal from the ABM Treaty (Dec. 13, 2001).

Elaine Monaghan, Clinton Planned Attack on Korean Nuclear Reactors, TIMES (London), Dec. 16, 2002.

George W. Bush, Commencement Address at the United States Military Academy in WestPoint (June 1, 2002), 38 WEEKLY COMP. PRES. DOC. 944, 946 (June 10, 2002).

Legality of the Threat or Use of Nuclear Weapons, Advisory Opinion, 1996 ICJ REP. 226 (July 8).

Military and Paramilitary Activities in and Against Nicaragua (Nicar. v. U.S.), Merits, 1986 ICJ REP.14, 103-04 (June 27).
Toby Sterling, Clinton: N. Korea Warned About Reactor, AP, Dec. 15, 2002, available in 2002 WL 104356190.

Treaty on the Limitation of Anti-Ballistic Missile Systems, May 26, 1972, U.S.-USSR, 23 UST 3435,944 UNTS 13.