What is the critical distinction between strategic, operational, and tactical levels of military doctrine?

The critical distinction between strategic, operational, and tactical levels of military doctrine lies in their scope, objectives, and time horizons. Strategic doctrine defines how military power supports national security goals. It deals with the broadest level of planning, focusing on aligning military actions with political objectives over the long term. An example would be a nation's overall policy on nuclear deterrence. Operational doctrine bridges the gap between strategy and tactics, outlining how military campaigns and major operations are conducted to achieve strategic objectives. It focuses on planning and executing large-scale military activities within a theater of operations, considering factors such as logistics, intelligence, and resource allocation. A joint operation combining air, land, and sea forces would be guided by operational doctrine. Tactical doctrine focuses on the execution of specific military tasks and battles at the unit level. It provides detailed guidance on how soldiers, vehicles, and weapons systems should be employed in combat situations. Infantry tactics for clearing a building in urban warfare are an example of tactical doctrine. Therefore, strategic doctrine concerns the 'why' of military action, operational doctrine addresses the 'how' of major campaigns, and tactical doctrine details the 'how' of individual battles and tasks. Each level informs the others, creating a hierarchy where tactical actions contribute to operational objectives, which in turn support strategic goals.