Lord Acton had more to say on liberty than he did on power corrupting.

Lord Acton on liberty, power, and the light of conscience

...Lord Acton would never be mistaken for an anarchist. In his view, exercising power and authority are necessary to preserve the order within society. However, he condemned absolute power, because it does not respect human dignity, something he found intimately bound up with liberty.

Yet Acton, who considered himself more of an historian than a philosopher, made clear in his two volumes The History of Freedom in Antiquity and The History of Freedom in Christianity that he believed the essence of the word liberty had never been well interpreted. Beginning with Jesus Christ’s teachings about liberty in the Gospel, he wanted to clarify this word, in order to avoid the misinterpretations, confusion, and polemics which he saw forming the basis of harmful political ideologies.

For Acton, “Liberty [is] not…the power of doing what we like, but the right of being able to do what we ought” (“The Roman Question.”). Alternately, liberty is “the assurance that every man shall be protected in doing what he believes his duty against the influence of authority and majorities, custom and opinion” (“The History of Freedom in Antiquity”).

Conscience takes priority for Acton. Commenting upon Lord Acton’s ideas, Christoph Bohr wrote: “No interests of any kind may limit a person’s right. Nothing and no one has the authority to interfere with the voice of the conscience.”...