Threats of Force: International Law and Strategy by Francis Grimal (review)

This book examines the character and legality of nation-states’ threats of force under international law, drawing its title from Article 2(4) of the United Nations (UN) Charter: “All Members shall refrain in their international relations from the threat or use of force against the territorial integrity or political independence of any state, or in any other manner inconsistent with the Purposes of the United Nations.” The article’s wording seems straightforward enough: most statesmen recognize unlawful uses of force when they see them, and hundreds of legal works are available to help dissect any areas of ambiguity. But identifying prohibited threats of force—as legally serious as actual uses, according to the author—forms the question at the heart of this book. How should lawyers and statesmen identify and respond to illegal threats of force under the UN Charter?

Astride the intersection of war and diplomacy, this short and readable volume is the author’s revised dissertation in international law. The first and second of the book’s seven chapters examine threats of force from 1648 to the present, determining how international law dealt with them (or mostly did not). Francis Grimal’s argument is that coerced states reacting to threats of force have lost their independence and are thus damaged by them. This perspective is a key assumption for the theoretical analysis that follows. Grimal contends that the failure to deal with threats of force is a serious risk to international peace and stability, frequently neglected not because of a lack of enforcement mechanisms but because of the imprecise wording and interpretation of Article 2(4) of the UN Charter. What is needed, he believes, is an objective categorization of legal and illegal threats, separate from historical or geopolitical contexts and known to all parties involved. Hence, he sets forth to create one.

Turning first to legal precedent, Grimal scrutinizes cases of the International Court of Justice as well as several national courts to find appropriate guidelines. Through a series of case studies in chapter three, he searches in vain for judgments that explain exactly what type of state threats of force violate the UN Charter. Yet statesmen do seem to recognize such threats when they see them. Chapter four assesses the UN’s record, including dozens of General Assembly and Security Council resolutions responding to threats of force—over Suez (1956), Cyprus (1963-1964), Kashmir (1965-1966), Western Sahara (1975-1976), and other international hotspots. (The book includes a handy 24-page appendix that summarizes dozens of cases.) Grimal concludes that, even in the absence of enforcement mechanisms, threats of force by state governments have not been tolerated by other UN member-states under international law, and that this constitutes de facto evidence of their significance to the international community. But the precise nature of prohibited threats remains to be clearly defined.

Grimal turns to strategy for guidance, focusing in particular on the works of Thomas Schelling and mid-20th-century deterrence theory. Drawing mainly from Schelling’s classic Arms and Influence, Grimal maintains that capability, credibility, communication, and commitment are the necessary characteristics of real threats. With the addition of just war concepts and hegemonic theory, the book then focuses on nuclear proliferation (particularly by Iran and North Korea) as a serious risk to the international community. Does withdrawal from the Nonproliferation Treaty (NPT) suffice as a threat of force? Is the acquisition of nuclear weapons an inherent threat of force, even in the absence of threatening behavior or statements? Given the nature and purpose of nuclear weapons, is any violation of the NPT a threat of force? The author parses these and other questions according to existing international law and strategic theory, concluding that the current formulation of Article 2(4) is ill equipped to deal with nuclear threats and thus inadequate for current challenges to international security.

In the final chapter, Grimal seeks to offer an alternative means of prohibiting threats of force by reinterpreting Article 2(4). He...