War without accountability. AI and the fragmentation of responsibility in contemporary warfare

The incorporation of artificial intelligence into security and defense domains has substantially transformed the nature of contemporary warfare, altering not only its operational capabilities but also one of its foundational pillars: the attribution of responsibility. In this new environment, military decisions no longer originate exclusively from clearly identifiable human agents but emerge from complex systems in which algorithms, data, technological infrastructures, state actors, and private companies interact. This article argues that the most profound impact of artificial intelligence in warfare does not lie solely in the automation of processes, but in the progressive fragmentation of responsibility, which complicates the identification of a single accountable subject for decisions and their consequences. In this sense, artificial intelligence does not merely introduce efficiency into military operations but rather produces a structural reconfiguration of responsibility through the fragmentation of the decision-making process, fundamentally altering how decisions and their consequences are attributed in armed conflict. Using an interdisciplinary approach, the article examines transformations in decision-making, the legal and ethical tensions arising from this phenomenon, and the strategic implications of increasing dependence on algorithmic systems. It introduces the notion of the “last human line” as a critical analytical point, representing the increasingly blurred boundary between human decision-making and automation, and highlights the need to rethink normative frameworks for a form of warfare in which responsible actors may be diffuse or virtually absent.