Prohibition of intervention

Definition

Prohibition of intervention

The obligation of non-intervention, a norm of customary international law prohibits States from intervening coercively in the internal or external affairs of other States. Prohibited intervention was authoritatively defined by the International Court of Justice in the judgment on the merits in the 1986 case Nicaragua v United States: A prohibited intervention must … be one bearing on matters in which each State is permitted, by the principle of State sovereignty, to decide freely. One of these is the choice of a political, economic, social and cultural system, and the formulation of foreign policy. Intervention is wrongful when it uses methods of coercion in regard to such choices, which must remain free ones. In order for an act, including a cyber operation, to qualify as a prohibited intervention, it must fulfil the following conditions: The act must bear on those matters in which States may decide freely. The spectrum of such issues is particularly broad and it includes both internal affairs (such as the “choice of a political, economic, social, and cultural system” or the conduct of national elections), and external affairs (“formulation of foreign policy”; “recognition of states and membership of international organisations”)—the so-called domaine réservé of States. The content of the domaine réservé is determined by the scope and nature of the State's international legal obligations. The act must be coercive in nature. There is no generally accepted definition of “coercion” in international law. In this respect, two main approaches have emerged in the cyber context: Under the first approach, an act is coercive if it is specifically designed to compel the victim State to change its behaviour with respect to a matter within its domaine reservé. Under this approach, the “key is that the coercive act must have the potential for compelling the target State to engage in an action that it would otherwise not take (or refrain from taking an action it would otherwise take)”. Under the second approach giving meaning to “coercion”, it is sufficient for an act to effectively deprive the target State of its ability to control or govern matters within its domaine reservé. This latter approach distinguishes itself from the former by accepting that mere deprivation of the target State’s control over a protected matter, without actually or potentially compelling that State to change its behaviour, may constitute intervention. Under both approaches, however, merely influencing the target State by persuasion or propaganda or causing a nuisance without any particular goal is insufficient to qualify as coercion. The element of coercion also entails the requirement of intent. Finally, there has to be a causal nexus between the coercive act and the effect on the internal or external affairs of the target State.

National positions

United Kingdom

"In certain circumstances, cyber operations which do not meet the threshold of the use of force but are undertaken by one state against the territory of another state without that state’s consent will be considered a breach of international law.

The international law prohibition on intervention in the internal affairs of other states is of particular importance in modern times when technology has an increasing role to play in every facet of our lives, including political campaigns and the conduct of elections. As set out by the International Court of Justice in its judgment in the Nicaragua case, the purpose of this principle is to ensure that all states remain free from external, coercive intervention in the matters of government which are at the heart of a state’s sovereignty, such as the freedom to choose its own political, social, economic and cultural system.

The precise boundaries of this principle are the subject of ongoing debate between states, and not just in the context of cyber space. But the practical application of the principle in this context would be the use by a hostile state of cyber operations to manipulate the electoral system to alter the results of an election in another state, intervention in the fundamental operation of Parliament, or in the stability of our financial system. Such acts must surely be a breach of the prohibition on intervention in the domestic affairs of states."

United Kingdom: 2021

"Below the threshold of the threat or use of force, the customary international law rule prohibiting interventions in the domestic affairs of States applies to States’ operations in cyberspace as it does to their other activities. As set out by the International Court of Justice in its judgment in the Nicaragua case, the purpose of the rule on non-intervention is to ensure that all States remain free from external coercive intervention in matters affecting a State’s powers, which are at the heart of a State’s sovereignty such as the freedom to choose its own political, social, economic and cultural system.

As the UK has noted previously, while the precise boundaries of this rule continue to be the subject of on-going debate, it provides a clearly established basis in international law for assessing the legality of State conduct. Thus the use of hostile cyber operations to manipulate the electoral system in another State to alter the results of an election, to undermine the stability of another State’s financial system or to target the essential medical services of another State could all, depending on the circumstances, be in violation of the international law prohibition on intervention.

The International Court of Justice has established that a prohibited intervention is one bearing on matters which each State is permitted, by the principle of State sovereignty, to decide freely."

United States of America: 2016

In certain circumstances, one State’s non-consensual cyber operation in another State’s territory could violate international law, even if it falls below the threshold of a use of force. This is a challenging area of the law that raises difficult questions. The very design of the Internet may lead to some encroachment on other sovereign jurisdictions. Precisely when a non-consensual cyber operation violates the sovereignty of another State is a question lawyers within the U.S. government continue to study carefully, and it is one that ultimately will be resolved through the practice and opinio juris of States.

Relatedly, consider the challenges we face in clarifying the international law prohibition on unlawful intervention. As articulated by the International Court of Justice (ICJ) in its judgment on the merits in the Nicaragua Case, this rule of customary international law forbids States from engaging in coercive action that bears on a matter that each State is entitled, by the principle of State sovereignty, to decide freely, such as the choice of a political, economic, social, and cultural system. This is generally viewed as a relatively narrow rule of customary international law, but States’ cyber activities could run afoul of this prohibition. For example, a cyber operation by a State that interferes with another country’s ability to hold an election or that manipulates another country’s election results would be a clear violation of the rule of non-intervention. For increased transparency, States need to do more work to clarify how the international law on non-intervention applies to States’ activities in cyberspace."

Appendixes

See also

• Scenario 01: Election interference
• Scenario 02: Cyber espionage against government departments
• Scenario 03: Cyber operation against the power grid
• Scenario 05: State investigates and responds to cyber operations against private actors in its territory
• Scenario 07: Leak of State-developed hacking tools
• Scenario 08: Certificate authority hack
• Scenario 14: Ransomware campaign
• Scenario 16: Cyber attacks against ships on the high seas
• Scenario 17: Collective responses to cyber operations