This 2002 article really speak wisely to the evils of power.
LoTR was an allegory on the subject.
Says Tolkien:
"You can make the Ring into an allegory of our own time, if you like: and allegory of the inevitable fate that waits for all attempts to defeat evil power by power" (The Letters of J.R.R. Tolkien, 1995, p. 121.)
"Power is an ominous and sinister word in all these tales" (p. 152.)
"The story is cast in terms of a good side, and a bad side, beauty against ruthless ugliness, tyranny against kingship, moderated freedom with consent against compulsion that has long lost any object save mere power, and so on" (pp. 178-179.)
"In my story Sauron represents as near an approach to the wholly evil will as is possible. He had gone the way of all tyrants: beginning well, at least on the level that while desiring to order all things according to his own wisdom he still at first considered the (economic) well-being of other inhabitants of Earth. But he went further than human tyrants in pride and the lust for domination, being in origin an immortal (angelic) spirit" (p. 243.)
Read the article and you will understand that using power to defeat evil power leads to disaster, because it is the power itself that is the evil.
This 2002 article really speak wisely to the evils of power.
LoTR was an allegory on the subject.