I. Through the Lens of Legality—
Formal Validity

- Jus ad Bellum: Crossing Borders to Wage War against Individuals
- – Christian Tams
- – James Devaney
- Who Can Be Killed?: Legal Targets in Non-International Armed Conflicts
- – Patrycja Grzebyk
- Boundaries of the Battlefield: The Geographical Scope of the Laws of War
- – Katja Schöberl
- Lethal Force and Drones: The Human Rights Question
- – Gloria Gaggioli


If there is a point of agreement among the scholars of legitimacy, it is on legality; that is, legality is always considered to be one of legitimacy’s central components.[1] Thus, the predominant scholars of legitimacy point to legality as a starting point. To do so in the context of counterterrorism it is important to take note of one distinctive feature of 9/11 that must shape the way we think about and analyze the response to them: these were cross-border attacks. Non-state actors stepped across international boundaries to conduct public and politically motivated violence against civilians. As a result, when citizens of the victim country, and even more critically the official members of the government itself, attempt to understand the rights and duties related to its response inevitably reaching outside of its domestic borders, international law is the natural, not to mention legally fitting, framework.
If there is a point of agreement among the scholars of legitimacy, it is on legality; that is, legality is always considered to be one of legitimacy’s central components.
Of note, there has been a dramatic increase in global cooperation throughout the twentieth century—between international organizations and their state missions of diplomats, foreign officers, international civil servants, intelligence officers, military personnel, police investigators, judges, legislators, and financial regulators—all governed by international law. These rules have mushroomed following the conclusion of each world war and this dramatic growth is arguably the most significant change the international structure has experienced since the inception of the state-based system ushered in with the Peace of Westphalia in 1648.
The contention here is that this surge in international regulation has had a bearing on the shape and content of the domestic political order. To suggest that this immense growth has had absolutely no effect on the domestic legal order or the mental framework for how citizens judge the obligations of their own government in an information age is to deny the shifting terrain. It is not a question of whether any adjustment has occurred, but rather the pertinent question is: How much change has actually come about?[2]
As it is posited that growing portions of civil society turn to international law to help understand and judge the legitimacy of their government’s counterterrorism policies reaching across international borders, this discipline undergirds our book with nearly all of its contributors credentialed or deeply grounded within it. To lay this foundation of formal validity, one must begin with the strength behind the logic of legal positivism and lay out a jurisprudential view of the applicable law. In consequence this section analyzes the applicable legal treaties, customary law as evidenced by state practice, general principles of law, and opinio juris in order to peer through the lens of legality.
As it is posited that growing portions of civil society turn to international law to help understand and judge the legitimacy of their government’s counterterrorism policies reaching across international borders, this discipline undergirds our book with nearly all of its contributors credentialed or deeply grounded within it.
There are four primary questions that are raised in international law when it comes to analyzing the lethal use of UCAVs for counterterrorism operations across borders, and each is explored in its own chapter. Those questions are: Is this use of force in the territory of another state justified? Who is a legal target in an armed conflict between a state and groups of individuals? Are there geographical limits to the application of humanitarian law—that is the laws of war? What is the proper application of human rights law when such deadly force is exercised?
Chapter 1
Jus ad Bellum: Crossing Borders to Wage War against Individuals
Christian Tams and James Devaney launch the investigations of this book with their chapter of preliminary relevance. Although the ban on the use of force across borders has been described as the “cornerstone” of the contemporary international system, the precise scope of the legal rules governing this prohibition is by no means beyond debate. The UN Charter lays down the legal framework, but the contours of the current interpretation of this shifting regime must be explored to understand where the law stands today when it comes to violent individuals and/or groups. As the use of armed drones has become a publicly recognized reality, this chapter argues that over the last 25 years the legal rules have been readjusted through interpretation to permit forcible counterterrorism under more lenient conditions. Nevertheless, the risks posed by current practice might indeed compel further readjustment to a legal regime undergoing stress as this act of force becomes more common.