by James A. Green. Oxford and Portland, Oregon: Hart Publishing, 2009. 246pp. Hardback. £47.00/$94.00. ISBN: 9781841138763.

Reviewed by Daniel C. Turack, Capital University Law School. Email: DTurack [at]


This book is an outgrowth of James A. Green’s Ph.D. thesis at the University of Nottingham. The attacks on the United States on 11 September 2001, and subsequent intervention of coalition forces in Afghanistan in 2001 and Iraq in 2003, have had an impact on the use of force (the jus ad bellum). Associated with the jus ad bellum is the universally accepted inherent right of self-defense. Increased scrutiny of this area of the law has involved the jurisprudential attention of the International Court of Justice (ICJ). This book is devoted to an examination of the relationship between the ICJ and the legal rules that comprise this area of international law.

Green begins with Article 51 of the United Nations (UN) Charter, the codification of the right of self-defense, both individually and collectively. However, he quickly draws the reader’s attention to universally accepted legal criteria that are prevalent in customary international law, but not present in Article 51, namely, the requirements of necessity and proportionality. His study considers the relationship between Article 51 and the customary rules as a central theme, and further attends to how treaty law and custom interrelate in this field.

The first time that the ICJ handed down a merits judgment on self-defense was in the 1986 Case of Military and Paramilitary Activities in and against NICARAGUA v. UNITED STATES OF AMERICA, that represented a complete assessment of the concept. Ten years later, the ICJ dealt substantively with self-defense in its Advisory Opinion on the Legality of the Threat or Use of Nuclear Weapons. This opinion was followed in 2003, in the contentious Case Concerning Oil Platforms, the Advisory Opinion of 2004, on the Legal Consequences of the Construction of a Wall in the Occupied Palestinian Territory, and the contentious Case of 2005, on Armed Activities on the Territory of the Congo (DEMOCRATIC REPUBLIC OF THE CONGO v. UGANDA).

It is not Green’s purpose to provide a comprehensive study of the law governing self-defense, but rather to identify crucial aspects in the Court’s jurisprudence governing the subject. I found it most beneficial for the author to set out very early on, the key pronuncements of the Court in respect of the five key cases.

Green initiates his specific focus on the criterion that comprises an “armed attack,” and its content, a fundamental aspect for the ICJ in the law on self-defense. Again, it is the Court’s conception, by the majority in the Court, not state practice, that is the focus, and other criteria involved are regarded as [*336] tangential or secondary. Factors considered by the Court are outlined in detail and shown in Table 1.2 (p.61), but Green finds “lack of clarity provided by the Court” (p.62).

Next, Green presents his assessment of the criteria of necessity and proportionality as found in customary international law. His starting point for state practice and opinio juris goes back to the Caroline incident of December 29, 1837, which has been referred to as the locus classicus of the law of self-defense. Of course, Green updates us on the Caroline formula in today’s context, and whether necessity’s interpretation as a “last resort” can be applied the same way in any given case. The proportionality criterion, as a requirement, brings its own complexities, admirably documented and illustrated by the author. Two temporal elements of customary international law regarding self-defense are discussed separately from “necessity” and “proportionality,” namely, imminence, that is, the need to respond is “instant, leaving… no moment for deliberation” (p.96), and immediacy, as an action of self-defense taken in response to an actual attack. He concludes that the ICJ has accurately characterized state practice and opinio juris in regard to the criteria of necessity and proportionality (p.105), and reaffirms their applicability to self-defense. However, “the Court has provided little guidance as to what they are” (p.108).

As Green finds the ICJ’s jurisprudence regarding self-defense to be problematic, he seeks to explore the underlying reasons. He reflects on the “armed attack as a grave use of force” criterion, and that of threat of necessity and proportionality, as a merged conception. The former intertwined criterion, he argues creates a concerning gap between Article 2(4) and Article 51 of the UN Charter. He then presents a proposal for dealing with the issue that will improve the current law. Along the way, he highlights key problems and the spectrum of thought on the Court, and academia, with regard to the complexities.

Green ends his analysis by partially exonerating the Court “in light of the extreme difficulty in attempting to reconcile the two interlinked ‘conceptions’ of self-defense as the law currently stands” (p.209), and advocates that the law on self-defense “should be reformed” (p.210).

There is a good index and bibliography; the tables of cases, treaties and conventions will help the reader to retrace one’s steps.

Legality of the Threat or Use of Nuclear Weapons, Advisory Opinion of 8 July 1996 – General List No. 95.
Legal Consequences of the Construction of a Wall in the Occupied Palestinian Territory, Advisory Opinion of 9 July 2004 - General List No. 131

© Copyright 2011 by the author, Daniel C. Turack.