Inside Cyber Warfare - Jeffrey Carr [36]
Additionally, the North Atlantic Treaty Organization, the Organization of American States, and Australia all invoked the collective self-defense provisions of their mutual defense treaties to assist the United States in its response to the 9/11 attacks. Finally, scores of other states declared their support for the United States to respond in self-defense to Al Qaeda. Given the universal outpouring of support to treat the 9/11 attacks as acts of war, it is now incontrovertible that states may apply self-defense law to armed attacks by nonstate actors.
However, while attacks by nonstate actors fall under the law of war, the law of war allows states to forcibly respond to these attacks only when the attacks are imputable to a state, meaning the state also bears some responsibility for the actions of the nonstate actors. The next step of the analysis toward imputing state responsibility for an attack is, therefore, to examine the duties that states have concerning nonstate actors within their territory.
Duties between States
It is a long established principle of international law that “a State is bound to use due diligence to prevent the commission within its dominions of criminal acts against another nation or its people.”[7]
This principle is reflected in numerous state declarations, judicial opinions, and publications from leading scholars. State declarations that support this principle include the 1970 Declaration on Friendly Relations, which urges states to “refrain from...acquiescing [to] organized activities within [their] territory directed towards the commission of [civil strife or terrorism in another state”; the 1994 Declaration on Measures to Eliminate Terrorism; and the 1996 Declaration on the Strengthening of International Security, which says that states “must refrain from organizing, instigating, assisting or participating in terrorist acts in territories of other states, or from acquiescing in or encouraging activities within their territories directed towards the commission of such acts.” International case law also supports this principle.
In Corfu Channel, the International Court of Justice held that states have a duty “not to allow knowingly its territory to be used for acts contrary to the rights of other States.”[8] In Tehran, it reaffirmed that states “are required under international law to take appropriate acts in order to protect the interests” of other states from nonstate actors within their borders.[9]
In short, it is clear from state practice and opinio juris, the two bases for customary international law, that states have an affirmative duty to prevent nonstate actors within their borders from committing armed attacks on other states. Toleration of such attacks constitutes a crime under international law.
Thus, when a host-state has the ability to prevent an armed attack by nonstate actors within its territory but fails to do so, it violates its duty under international law. However, since it is not realistic to expect states to completely prevent armed attacks by nonstate actors, the dispositive factor in evaluating state conduct is what a state does to address potential threats and whether it takes realistic steps to prevent the attack from occurring.
In and of itself, the duty to prevent attacks does not make states responsible for every cross-border attack by nonstate actors that emanates from their territory. However, it does bridge the gap between the actions of nonstate actors and the state. The next section completes the analysis of imputing state responsibility for the cross-border attacks of nonstate actors.
Imputing State Responsibility for Acts by Nonstate Actors
The question of a state’s legal responsibility for the acts of nonstate actors has evolved significantly over the past few decades. Before 1972, states were generally not viewed as legally responsible for the acts of private or nonstate actors.