“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 the Earth. But he went further than human tyrants in pride and the lust for domination, being in origin an immortal (angelic) spirit.
“In The Lord of the Rings the conflict is not basically about ‘freedom’, though that is naturally involved. It is about God, and His sole right to divine honour. The Eldar and the Númenóreans believed in The One, the true God, and held worship of any other person an abomination. Sauron desired to be a God-King, and was held to be this by his servants; if he had been victorious he would have demanded divine honour from all rational creatures and absolute temporal power over the whole world.”
“You can make the Ring into an allegory of our own time, if you like: an allegory of the inevitable fate that waits for all attempts to defeat evil power by power.”
―J.R.R. Tolkien, The Letters of J.R.R. Tolkien