Domains apart: how common terminology masks divergent U.S. and NATO Multi-Domain Operations concepts

Multi-Domain Operations (MDO) has become a central concept in contemporary Western military transformation, yet its meaning remains unsettled. This conceptual unclarity is problematic given that MDO is actively being implemented in armed forces ranging from the U.S. via NATO to countries like India and Japan. This article clarifies what MDO entails by comparing the two most influential formulations of the concept: the U.S. Army’s operationally focused MDO and NATO’s alliance-wide MDO concept. Through a structured comparison of doctrinal publications and related policy documents, this study shows that the U.S. Army conceives MDO as a service-specific warfighting concept aimed primarily at penetrating and disintegrating adversary anti-access area denial systems, whereas NATO employs MDO as a broader framework for deterrence, crisis management and the integration of military and non-military instruments of power. By distinguishing these conceptual logics, the study provides practitioners and policymakers with clearer definitions that can inform research, interoperability efforts, capability development, and multi-domain integration across the alliance.