by Keiichiro Okimoto. Oxford and Portland, Oregon: Hart Publishing, 2011. 389pp. Cloth £57.00/ $114.00. ISBN 978-1-84946-55-2

Reviewed by Wade Mansell, Kent Law School, University of Kent, Canterbury, UK. Email: W.M.Mansell [at]


For those unfamiliar with public international law the title of this book might well be opaque if not mysterious. When the Latin phrases are translated however the purpose and scope of the work becomes clear. In essence jus ad bellum describes the principle of international law that recognises a legal right for a state separately or in cooperation with allied states to engage in armed hostilities against another state or states. The literal meaning of the phrase is ‘right to war’. Thus to take the most uncontroversial case, a state has an international legal right (jus ad bellum) to act in self-defence if it has been attacked by another state or states. (Of course even this example is less straight forward than it might appear, as necessary questions will have to be considered concerning, among others, whether an attack really had occurred, whether there might be any right of ‘preventive’ self-defence, and whether any act of self-defence must be proportionate.) The doctrine of jus ad bellum describes the grounds of justification necessary for a state to legitimately engage in hostilities (including the use of force) with another state or states. If the doctrine is satisfied, individual combatants will be able to use violence without fear of criminal prosecution (as long as they do not breach international humanitarian law). It is the constraints upon the sort of force that may be used that is covered by the phrase jus in bello (literally ‘right in war’ and otherwise known as humanitarian law). Thus when international hostilities have commenced, or even indeed where non-international armed conflict has broken out, international law seeks to provide rules and principles to govern the conduct of combatants and for the protection of non-combatants. The aim of international humanitarian law is to mitigate the unnecessary suffering caused by armed conflict.

The history of international humanitarian law is, at first sight, curious because the preoccupation with how war was to be waged pre-dated discussion of when it might be permissible to wage it. International law concerned with limiting the inhumanity of war has a history dating back to the middle of the nineteenth century while the right of a state to wage war remained unconstrained until after the First World War. Equally curiously in so far as rules concerning jus ad bellum were developed earlier, they were concerned only with rights of self-defence and these arose from the so-called Caroline affair which occurred in 1837 and was resolved in 1841in an exchange of letters in an exchange of diplomatic notes between the U.S. Secretary of State and the then British Foreign Minister. [*519]

The genesis of international humanitarian law lies in two important sources. The first was the founding of the International Red Cross in 1863 created in response to the appalling suffering caused on battlefields and beyond with the development of new and more terrible weapons, and the second came from the United States at the same time, where an American lawyer, Francis Lieber, drafted what he wanted to be a statement of the laws and customs of war. (Probably not insignificantly he apparently had friends and relatives on both sides of the American Civil War.) The resulting Lieber Code was issued as ‘Instructions for the Government of Armies of the United States in the Field’. In the words of Brian Simpson (2001, p.97),

"The Lieber Code stated a fundamental principle: ‘Men who take up arms against one another in public war do not cease on that account to be moral beings, responsible to one another and to God.’ It laid down principles designed to reduce suffering by non-combatants, to limit reprisals, to provide for the humane treatment of prisoners and wounded, to regulate the use of flags of truce, and to limit the severity of measures taken under martial law. Versions of the Code were adopted by other armies, for example by Germany, and so it acquired an international character. In any case it purported to state international law, not American law. Lieber’s innovative attempt to express the demands of humanity in legal form encouraged the powers to produce formal agreements (variously called Declarations, Conventions and Protocols) on aspects of the laws of war." (2001, p.97, notes omitted; For a discussion of the Lieber Code, see Hartigan, 1983).

In the twenty-first century international humanitarian law is primarily to be found in the four Geneva Conventions of 1949 together with their two Protocols of 1977 It also includes the Hague Conventions of 1899 and 1907 (especially Hague IV with annexed Regulations which provided international norms on the methods and means of combat and are now regarded as customary international law if not general principles of international law) and a number of other treaties covering particular means of warfare such as chemical and biological weapons, and/or toxic gas.

In the view of most international lawyers jus ad bellum is now governed by the UN Charter which effectively proscribes the use of force in international law (by Article 2(4)) unless that force is either an act of self-defence (as provided for in Article 51) or is an act pursuant to a UN Security Council Resolution as provided for under Chapter VII of the Charter. These rules developed the provisions of the Covenant of the League of Nations of 1919 that had attempted to limit the right to go to war, at least until after other avenues for a peaceful resolution of an international dispute had been explored; and the seminal 1928 ‘Pact of Paris on the Renunciation of War as an Instrument of National Policy’ which purported to prohibit the waging of war. (Although this Pact was demonstrably unsuccessful, it was relied upon by the International Military Tribunal at Nuremburg in the prosecution of the Nazi leadership.)

The book under review is less concerned [*520] with the history of jus ad bellum and jus in bello than with their current relationship. A central question addressed by the book is ‘when a state wages an illegal war, do the victims of war of that state still benefit from the protection provided by jus in bello?’ and the answer provided is that

Gradually a consensus emerged on two principles which developed through state practice and opinions of experts: jus ad bellum and jus in bello should be kept separate and jus in bello applies equally to the conflicting parties, regardless of who started the conflict and whether it was lawful or not. These emerged from the conviction that all victims of armed conflict should be protected equally solely on the basis of humanitarian consideration and not the legal status of the conflicting parties under jus ad bellum.

Furthermore following Chapter VII of the UN Charter and common Article 3 of the 1949 Geneva Conventions and the 1977 Second Additional Protocol it was clear that rules regarding the use of force and also jus in bello applied equally to the use of force within a state and not only between states.

The body of the book is a careful excavation (not untypical of a good PhD thesis which is where this book began) of the interaction and relationship of jus in bello and jus ad bellum. The complexity of the task should not be under-estimated, nor its political significance. It has to be said that, perhaps understandably, this work is circumspect in the criticisms that it makes of states apparently manifestly in breach of the rules identified. (One example of many is to be found in the discussion of the US attacks on Al-Qaeda bases and members in Afghanistan – or more particularly, Yemen, and whether the US was legally justified in this response to the attack on the US on 11 September 2001, see pages 64 and 65.) Further it does not really examine recent attempts, particularly by the US to suggest that the application of the Geneva Conventions should not be universal. For that, the reader might consult Perrigo and Whitman THE GENEVA CONVENTIONS UNDER ASSAULT (Pluto Press, 2010).

For international lawyers concerned with the application of international humanitarian law this book will be indispensable, but if I have one major criticism it is that, in the words of the author in a different context (page 300), ‘Here the law and reality seem to be quite far apart’. After the interventions in Kosovo and Libya, the internal turmoil in Egypt, continuing chaos in Afghanistan, fearful forceful intervention in Gaza by Israel, appalling human rights abuses by or between combatants in the Democratic Republic of the Congo, Somalia, Mali and other African states, and now most prominently the tragic Syrian humanitarian catastrophe, this dispassionate analysis of rules that supposedly constrain and govern these events sometimes feels as though it is addressing a parallel universe (as perhaps in some senses it is). Constant attempts by women and men of goodwill to address this disjuncture, most recently through the concept of a ‘responsibility to protect’, seem unable to curb the violent excesses prominent in so many countries in the world. [*521]

Of course the author of the book could fairly respond by suggesting that I am critical of something that is not the object of the book. I readily concede this but would nevertheless maintain that legal doctrine must necessarily be held up to the light of political reality. The fact that it is then found wanting, is not the fault of Keiichiro Okimoto.


Hartigan, R.S. 1983. LIEBER’S CODE AND THE LAWS OF WAR. University of Chicago Press.

Perrigo, Sarah, and Jim Whitman (eds). 2010. THE GENEVA CONVENTIONS UNDER ASSAULT. Pluto Press.

Simpson, A.W.B.. 2001. HUMAN RIGHTS AND THE END OF EMPIRE. Oxford University Press.

Copyright 2013 by the Author, Wade Mansell