Moral authority is authority premised on principles, or fundamental truths, which are independent of written, or positive, laws.
Marco Rubio: President had legal, moral authority to attack by Fox News
As such, moral authority necessitates the existence of and adherence to truth.
Daniel Hannan on the EU's lack of moral authority by DanHannan
Because truth does not change, the principles of moral authority are immutable or unchangeable, although as applied to individual circumstances the dictates of moral authority for action may vary due to the exigencies of human life.
These principles, which can be of metaphysical and/or religious nature, are considered normative for behavior, whether they are or are not also embodied in written laws, and even if the community is ignoring or violating them.
Therefore, the authoritativeness or force of moral authority is applied to the conscience of each individual, who is free to act according to or against its dictates.
Moral authority has thus also been defined as the "fundamental assumptions that guide our perceptions of the world".