What Is the Extent of Self-Defense by a State?

Emory University School of Law's Laurie R. Blank (who heads Emory's International Humanitarian Law Clinic) is a leading and prolific scholar and practitioner in the field of the law of armed conflict (and occasional Lawfare contributor). Her new column in the Jurist, "Self-Defense Against Terrorists: How Long and How Far" (March 11, 2017), provides a crisp statement on the much-debated issue of the extent and duration of a state's right of self defense against terrorist groups and violent non-state actors. The column is drawn from a scholarly article, forthcoming in the Israel Yearbook of Human Rights (2017), "The Extent of Self-Defence Against Terrorist Groups: For How Long and How Far?" (available at SSRN, here).

Blank notes that much of the legal debate over self-defense and non-state actors has been conducted around whether there is such a right and, if so, what triggers it. These two articles, by contrast, start from the position (by way of a background discussion that includes analysis of contemporary state practice) that states have such a right and move onward from that to questions of its extent and duration. Thus, the Jurist column begins with the obvious yet still relevant observation that:

the US campaign against al Qaeda and its affiliates — often termed "associated forces" — is now in its sixteenth year and does not appear to be ending anytime soon ... The passage of time alone raises a critically important question: how long does self-defense last? And as the US has shifted its stated objective from preventing future attacks to "ensuring the lasting defeat of al Qaeda and violent extremist affiliates," a second essential question is how far can a state go — both in the geographic sense and in the sense of the legitimate aims of using force — when acting in self defense?

These questions will, of course, be familiar to regular readers of Lawfare, Just Security, EJILTalk and the voluminous academic and policy literature on self-defense and violent non-state actors (e.g., Ashley Deeks on "unwilling or unable"; Bobby Chesney, Rebecca Ingber, and many other Lawfare contributors on whether the original AUMF still carries legal force for contemporary operations—and, for that matter, my 2015 book with Benjamin Wittes, Speaking the Law).

The Jurist column frames answers to these questions (and a host of others that follow from them) by laying out the relevant categories of law—jus ad bellum questions, jus in bello, etc.—accessibly for the non-specialist. The Israel Yearbook academic article lays out Blank's substantive analysis of these issues, combining careful scholarly work with common-sense consideration of state practice in this area and the practicalities of contemporary military operations. Here is the SSRN abstract to the Israel Yearbook of Human Rights article:

The post-9/11 environment, in which states may use self-defense as an ongoing and overarching justification and construct for military operations, whether episodic or sustained in nature, against one or more non-state groups for more than fifteen years, poses challenges to the very concept of self-defense. In particular, the ongoing reliance on self-defense in locations and against groups not contemplated at the time of the initial incident triggering the right to self-defense raises essential questions about the extent of self-defense: how far can a state go when acting in self-defense — both in the geographical sense and in the sense of the legitimate aims of using force — and for how long does this right of self-defense last? In this era of extended campaigns against transnational terrorist groups, examination of such questions is essential to an understanding of self-defense and, therefore, an effective assessment of the legality of state action against such groups.

This article explores the extent of self-defense, particularly in the context of a state using force in self-defense against one or more terrorist groups located in one or multiple locations outside the boundaries of the State. After brief foundational background, the article examines how differing conceptions of the legitimate aims of self-defense affect the extent of self-defense and addresses the consequences of an armed conflict paradigm for the parameters of self-defense. Finally, the article raises questions that naturally follow from a state's initial success in countering a terrorist group with armed force and pose new challenges for the self-defense analysis. For example, as a state's military operations damage a group's ability to operate, it will seek new bases from which to operate in different states or regions and it may splinter into multiple groups or reconstitute itself as one or more new groups. Along with the appearance of new groups inspired by or declaring allegiance to the original terrorist group, these developments require further analysis of whether the nature and extent of self-defense changes, and how, in light of the dynamic operational environment for counterterrorism.