The principle of proportionality in attack is a fundamental concept in the law of armed conflict, aiming to balance military necessity with humanitarian considerations. Its evolution reflects centuries of legal, ethical, and strategic debates, shaped by both customary international law and codified treaties. Historically, proportionality emerged from the recognition that warfare, while inherently destructive, must maintain limits to protect civilian populations and prevent unnecessary suffering. Early formulations can be traced to the writings of thinkers like Hugo Grotius and Emer de Vattel, who emphasized restraint and the moral obligations of combatants. These early ideas laid the groundwork for more formal legal codifications that appeared in the late 19th and 20th centuries. The evolution of proportionality has been closely tied to the development of international humanitarian law (IHL), particularly the Geneva Conventions and their Additional Protocols. Article 51(5)(b) of Additional Protocol I explicitly articulates that attacks must not be excessive in relation to the anticipated military advantage. This introduced a measurable, though often interpretive, standard for commanders to weigh the expected harm to civilians against the military gain. Proportionality is not absolute; rather, it recognizes that some incidental civilian harm may occur, but such