Which term describes the concept of ruling by moral sanction rather than necessity?

The chosen answer, legitimacy, is correct because it refers to the acceptance of an authority, usually a governing law or a regime, as being appropriate and justified. When a governing body rules through moral sanction, it derives its power from a belief in its ethical validity and the support or consent of the governed, rather than through coercion or necessity. This idea emphasizes the role of shared values, traditions, and the inherent belief in the rightness of authority, establishing a connection with the populace that fosters stability and order.

In contrast, despotism involves the exercise of absolute power, often without moral consideration or consent from those being ruled. Autonomy relates to independence and self-governance but does not directly pertain to the nature of authority based on moral grounding. Consensus, while it involves agreement and collective support, may not always account for the moral legitimacy of the ruling authority itself. Therefore, legitimacy focuses specifically on the acceptance and moral justification of governance, making it the most appropriate answer to the question.