LENS Essay Series: “Mind the Gap? Jus as Bellum and Jus in Bello in the Era of Hybrid Warfare”

Do you know what “hybrid war” means?  Does international law consider it “war” or “peace”?  How should the law assess it?  Does it matter?

In “Mind the Gap? Jus ad Bellum and Jus in Bello in the Era of Hybrid Warfare,” the latest installment of the LENS Essay Series, Duke Law’s amazing 3L Riley Flewelling expertly addresses these questions and more. 

Some context: there is a difference between jus ad bellum and jus in bello.  Essentially, jus ad bellum governs the legality of the resort to war, while jus in bello governs the conduct of war once it’s underway.  This traditional dichotomy between legal frameworks, Riley tells us, is no longer clear.  She contends:

Modern “wars” do not always make it to the battlefield, and those that do are waged using larger “arsenals” than ever before. In a world of information operations, little green men, hotter border disputes, targeted killings, and lawfare, it is unclear if the jus ad bellum and jus in bello frameworks can, or should, stay in their individual boxes. Further, these legal frameworks do not present a binary choice of response for states. International law offers other outlets for resolving state conflict.

She argues that some adversaries are exploiting the lack of clarity through the phenomena of hybrid war:

“Hybrid warfare is understood as the effort to use all instruments, elements, and determinants of power in a coordinated, comprehensive, and holistic way (including violence or the threat of violence) to achieve [a] political end.” It seeks to blur lines and confuse conventional understandings of war and escalation, which often involves exploiting areas where there are seeming legal gaps in the international system. (Citations omitted)

Does it matter?  Definitely.  Riley cites a recent speech by Department of Defense General Counsel Caroline Krass about cyber operations that raises parallel concerns about escalation when legal standards are unclear:

Krass explicitly acknowledges that clear legal standards prevent inadvertent escalation, and then explains a category of U.S. action called “campaigning,” or activity in “the gray zone…that is, on the spectrum of competition below the level of or outside the context of armed conflict.”  Tying together these ideas, Professor Michael Schmitt noted that clear legal thresholds are crucial for such engagement because “effective campaigning necessitates understanding the rules of the game” to prevent unjustified state responses.  (Citations omitted)

Want more about what you’ll read?  Take a look at Riley’s abstract of her article:

The international community has long relied on jus ad bellum, or the legal framework governing state use of force, and jus in bello, or the legal framework governing conduct in war, to manage and define state conflict. But in the era of hybrid warfare, conflicts often play out in the legal gaps and areas of ambiguity between these frameworks. In a world of information operations, little green men, hotter border disputes, targeted killings, and lawfare, it is unclear if jus ad bellum and jus in bello can keep up. States such as Russia and China consistently exploit areas of international legal ambiguity to further their own ends, and this phenomenon shows no sign of stopping.

This paper explores the legal gaps between and around the jus ad bellum and jus in bello frameworks and questions how they might be changed to better handle the realities of hybrid warfare. Building off prior scholarship which has assessed these gaps, this paper ultimately argues against extending these legal frameworks to create coverage for every aspect of modern conflict, while also briefly discussing other legal tools which could be used to create holistic state responses to hybrid warfare. (Emphasis added.)

Riley writes not only with the expertise of a savvy scholar, but also with a refreshing verve and clarity that makes her ideas accessible to everyone.  Be sure to check out her essay here.

About the Author

Riley FlewellingRiley Flewelling (J.D./L.L.M. 2024) is a third-year at Duke University School of Law. She hails from Colorado Springs, Colorado and graduated from Dartmouth College with a B.A. in Government in 2021. During her 1L summer, Riley externed with the US Air Force JAG Corps and studied at the Duke-Leiden Summer Institute in the Netherlands. During her 2L summer, she worked in Washington, D.C. as a Summer Associate with Crowell & Moring. At Duke, Riley serves as Co-President of the National Security Law Society and is a Notes Editor for the Duke Law Journal.

Remember what we like to say on Lawfire®: gather the facts, examine the law, evaluate the arguments – and then decide for yourself!

You may also like...