What term describes the broad and enduring purposes for which the Services and the Combatant commands were established by law?

The term that describes the broad and enduring purposes for which the Services and the Combatant commands were established by law is "Roles." This term encompasses the fundamental duties and responsibilities assigned to each branch of the military and the combatant commands, as defined by legislation. It reflects the overarching framework within which these entities operate, ensuring clarity in their missions and organizational structure.

Understanding "Roles" is essential because it captures the essence of what each military service is mandated to do, shaping how they fulfill their obligations to national defense and security. This concept provides a foundation for strategic planning and execution, ensuring that each branch and command remains aligned with its statutory purposes.

The other terms do not encapsulate the intent of the question as effectively. Functions refer to specific actions taken by the military components, strategies imply targeted plans to achieve specific objectives, and pillars may denote supporting aspects of broader doctrines but do not directly represent the legal purposes established for the Services and Combatant commands. Thus, "Roles" is the most accurate term in this context.