International Humanitarian Law and the Conduct of Hostilities: Proportionality Assessment in Nigeria’s Counter-Insurgency Operations

This research provides an original analytical and empirical assessment of proportionality under international humanitarian law (IHL) in Nigeria's counter-insurgency operations, focusing on documented military actions in the Lake Chad Basin region between 2020 and 2024. Proportionality, as enshrined in Article 51(5)(b) of Additional Protocol I and reflected in customary international humanitarian law, prohibits attacks expected to cause incidental civilian harm excessive in relation to the anticipated military advantage. Using an analytical IHL methodology combined with systematic review of military operation reports, human rights organisation documentation, UN Secretary-General reports, and media evidence, the study develops a proportionality assessment framework applicable to Nigerian counter-insurgency contexts and applies it to a sample of twenty documented military actions. It fills a critical gap in the existing literature by applying a structured proportionality analytical framework to African counter-insurgency rather than relying on anecdotal human rights reporting. Findings indicate a pattern of operations where the proportionality analysis was likely inadequate, with insufficient pre-attack assessment of civilian presence and limited after-action review of civilian harm. The study makes a methodological contribution by developing and testing a proportionality assessment tool designed for use by legal advisors in African military operations. Recommendations include mandatory IHL legal advisor integration in operational planning cells, adoption of civilian casualty tracking systems, and standardised proportionality review procedures. Keywords: proportionality, IHL, counter-insurgency, civilian protection, Nigeria.