Mbori Otieno, Emmah Wabuke, and Smith Otieno,
The Fission and Fusion in International Use of Force: Relating Unlawful Use of Force and the War Crime of Disproportionate Force Not Justified by Miitary Necessity,
48 Case W. Res. J. Int'l L.
Available at: https://scholarlycommons.law.case.edu/jil/vol48/iss1/15
Jus ad bellum and jus in bello are not disparate in operation. There are several points of intersection in the two concepts, commencing with the context in which they apply, and further, in their interpretation of the general principles of proportionality and necessity. Although proportionality connotes divergent theoretical notions depending on the backdrop against which it is set, in practice, these notions are often fused together. However, points of fission (divergence) still persist. The best example of which is in the context of 'The Crime of Disproportionate Use of Force' where the difference between the two notions of 'proportionality' can be described as the limitations on the overall force used to respond to an armed attack under jus ad bellum as opposed to the balance between the anticipated military advantage weighed against the resulting loss of civilian life under jus in bello. The authors argue that there is need for fusion (convergence) between jus ad bellum and jus in bello particularly in relation to modern war crimes trials in order to ensure that both principles have practical significance. This would ensure further convergence between jus in bello and jus ad bellum. To fulfill the shielding purpose of law in the context of armed conflict, more fusion between these two concepts must be embraced in all fora, including, conceptualization of crime of aggression and distinguishing between combatants and civilians.