Law Commons^™

The Plea Of Necessity: An Oft Overlooked Response Option To Hostile Cyber Operations, Louise Arimatsu, Michael N. Schmitt

International Law Studies

States are increasingly focused on the measures—cyber or otherwise—that they can take in response to hostile cyber operations. Although cyber operations are usually responded to with acts of “retorsion” (acts that are lawful, although unfriendly), international law recognizes other self-help mechanisms that allow for more robust responses. In the cyber context, most attention has focused on countermeasures and self-defense. Yet, both are subject to various limitations that constrain their availability.

This article examines a further option, the so-called “plea of necessity.” It allows States to respond to a hostile cyber operation when the action taken would otherwise be unlawful but …

Cyber Attribution And State Responsibility, William Banks

International Law Studies

We might expect international law to specifically address cyber attribution requirements due to the significance of attribution in framing the legal responsibility of States and the boundaries of responsive actions by victim States. However, there is little international law of cyber attribution, and what law there is exists largely by implication. Likewise, there is only a murky and highly contested law of State responsibility that theoretically constrains the vast majority of State-sponsored cyberattacks. Because victim States cannot engage in countermeasures unless they attribute a cyberattack to a State, attribution can serve simultaneously to constrain and empower victim States. However, the …

Responding To Hostile Cyber Operations: The “In-Kind” Option, Michael N. Schmitt, Durward E. Johnson

International Law Studies

Facing hostile cyber operations, States are crafting responsive strategies, tactics and rules of engagement. One of the major challenges in doing so is that key aspects of the international law governing cyber responses are vague, unsettled or complex. Not surprisingly, therefore, international law is markedly absent from strategies and operational concepts. Rather, they tend to take on a practical “tit-for-tat” feel as policymakers logically view “in-kind” responses as “fair play.” For them, responding in-kind surely must be lawful notwithstanding any challenges in discerning the precise legal character of the initial hostile cyber operation.

Testing that sense, this article examines the …