Which principle of war is focused on ensuring operations are conducted under a single overarching command?

The principle of war that emphasizes the importance of conducting operations under a single overarching command is Unity of Command. This principle ensures that all forces involved in an operation are directed by one commander, facilitating clear lines of authority and responsibility. This unity helps to avoid confusion and ensures that all elements of the operation work towards a common objective, making coordination more effective.

When a single commander is in charge, it becomes easier to synchronize efforts, allocate resources efficiently, and maintain a cohesive strategy across various forces. This results in improved operational efficiency and effectiveness, as all units can execute their tasks in concert rather than at cross-purposes, thereby increasing the likelihood of mission success.

In contrast, the other options do not specifically address the concept of command structure or authority over operations. Mass relates to the concentration of combat power, Economy of Force pertains to allocating minimal resources to non-essential tasks, and Simplicity emphasizes clear and uncomplicated plans. None of these principles specifically focus on the command aspect as Unity of Command does.