HYBRID WARFARE AND THE LIMITS OF INTERNATIONAL HUMANITARIAN LAW: DISTINCTION, PROPORTIONALITY AND MILITARY NECESSITY IN THE SYRIAN AND UKRAINIAN CONFLICTS

Abstract

This article examines how far International Humanitarian Law (IHL) responds to hybrid warfare, understood as the coordinated combination, by a state or a state-sponsored or tolerated actor, of conventional or irregular military force with cyber, informational or economic instruments. Adopting an interpretivist, qualitative multiple-case design, it applies a Hybrid Warfare Continuum and a Legal Response Matrix to the Syrian civil war and the Ukraine conflict, the latter spanning a deniable phase (2014–2021) and an overt interstate phase (from 2022). It finds that IHL applies with formal clarity to the conventional end of the continuum, but that its practical application is persistently complicated: classification is not self-executing and is recognized only after considerable delay; distinction is strained by the proliferation of armed actors of uneven discipline; proportionality assessed strike by strike fails to capture the cumulative harm of sieges and urban bombardment; and military necessity is exposed to rhetorical inflation. The gap is therefore predominantly implementational rather than doctrinal. Four reform implications follow: clearer classification criteria; investigative capacity designed to trace responsibility across layered sponsorship; coordinated development of IHL alongside sovereignty, cyber and human rights law; and strengthened rules on humanitarian access.