Adequacy of the ex post armed attack framework of the Jus Ad Bellum in relation to the evolving means and methods of warfare

Abstract

Jus ad bellum, the international law on the use of force, comprises rules that, by and large, predate many game-changing milestones in the evolution of warfare. The drafters of the 1945 United Nations Charter, the quintessential text of this body of law, could not have foreseen the advent of the matchlessly destructive nuclear arms, the creation of the fifth domain of warfare (cyberspace) or, for that matter, the precipitous surge in the incidence and gravity of asymmetric conflicts. That being the case, states and scholars have long been locked in a disagreement over how, if at all, to adjust the relevant norms to the changes on the battlefield. The present thesis offers a critical perspective on the adaptive shortcomings of the jus ad bellum, focusing specifically on the ex post armed attack framework of the right to self-defence, i.e. the precepts that regulate the use of force against ongoing and concluded offensives. The said framework separates lawful self-defence from the unequivocally unlawful armed reprisals. While deceptively straightforward on the surface, the self-defence/reprisal dichotomy is confounded by the lack of academic consensus on the distinguishing markers of the two doctrines. Cognizant of the ambiguity at play, this project poses a two-pronged research question: what are the contemporary parameters of the ex post armed attack framework, and do they adequately accommodate the post-1945 means and methods of warfare?

To answer the first half of the query, the present study composes a comprehensive picture of the post-1945 state practice and opinio juris, thereby revealing the ever-elusive line between self-defence and armed reprisals. The resulting output is a unique three-step methodology for the identification of armed reprisals, a tool that is then used as a benchmark for the second contribution to the scholarship, that is, the assessment of whether the legal status quo is reconcilable with modern threats and challenges. The conclusion reached is that, whilst reprisals continue to be illegal, some of their historically exclusive features have, owing to the unprecedented innovation in warfare, been transposed into the doctrine of self-defence. As regards the law’s effectiveness at keeping up with the practical realities, the present thesis finds that, although the jus ad bellum has come a long way in adapting to its operational environment, there remain significant deficiencies in its regulation of, most notably, cyber-attacks and safe havens for non-state aggressors.