I believe that Sauron's power was very great indeed, he was the lieutenant of Morgoth, his second in command and this certainly demonstrated his power or at least his malevolence. He was skilled in treachery which was one of his greatest assets: he coerced Ar Pharazon into sending a fleet to the Lords of the West and thus the downfall of Numenor, Sauron coerced Celebrimbor and the elves of Eregion into forging the Rings of Power. His power in coercion seemed endless, however your question is quite vague, what kind of power do you mean, actual physical power or the power of the mind, coercion and creating disharmony. Sauron was certainly a master of this, in addtion he created the master ring and tricked the elves, we all know how poerful the ring could be so i believe he did have power of all types.
|