Smartphones in the Fog of War: Civilian Intelligence Apps and the Boundaries of International Humanitarian Law

This article examines the legal implications of civilian intelligence applications used during armed conflict, focusing on smartphone-based reporting systems deployed in the Russian–Ukrainian war. Applications such as Ukraine’s e-Enemy feature integrated into the Diia platform and the standalone ePPO application have enabled civilians to provide real-time geolocated information concerning troop movements, missile trajectories, and military activities. While these technologies provide substantial operational advantages, they simultaneously challenge foundational principles of International Humanitarian Law (IHL), particularly the distinction between civilians and combatants. The article critically evaluates whether civilians using such applications engage in direct participation in hostilities (DPH) under Article 51(3) of Additional Protocol I, analysing the criteria of threshold of harm, direct causation, and belligerent nexus. It argues that although certain forms of real-time operational reporting may satisfy the DPH threshold in limited circumstances, existing doctrine remains insufficient to address the broader systemic implications of state-organised digital civilian mobilisation. The article further contends that embedding military intelligence functions within civilian digital infrastructure transforms such platforms into potential dual-use objects, thereby engaging state obligations under Articles 48, 52, 57, and 58 of Additional Protocol I, as well as Common Article 1 of the Geneva Conventions. Through doctrinal analysis and the Ukrainian case study, the article proposes the development of a “duty of digital separation” requiring states to maintain clearer distinctions between civilian services and military intelligence systems. It additionally advocates enhanced precautionary duties, informed consent mechanisms, risk disclosure obligations, and governance frameworks for civilian intelligence applications. Ultimately, the article demonstrates that while IHL remains technologically adaptable in principle, interpretative refinement is necessary to preserve civilian protection in the context of digitally mobilised warfare.