Likely spurred by reading the Tolkien criticism, then hearing a few people who are quite sure they are (collectively) very nice saying some hateful things, it occurred to me that we tend to become what we hate.
No, I didn't say that quite right. I don't mean it in St Paul's sense of doing what we hate, nor that we become opposites, reacting against our earlier selves, though both of those are related. When we hate something or someone, we ascribe particular bad qualities to them. Those may or not be true about the other person or group, yet we come to believe them strongly. Believing this, we consider ourselves guiltlesss in opposing such evil folk. We are in fact righteous for doing so.
There is a psychological defense mechanism called projection, in which we attribute feelings to others that are actually our own. You aren't listening to me! says the one who isn't listening. We usually use this term about negative feelings such as anger or jealousy, but we can project good feelings onto others as well, imagining them to be better than they are, or to be as fond of us as we are of them. Barack Obama noted explicitly that people saw in him what they wanted to see, and played to that. It is likely one of the functions celebrities, including leaders, provide for us.
Putting the two ideas together, I am convinced that the projection may start immediately at some full level, but it deepens as it goes forward. The hatred of the other comes back to us, in much the same form we sent it out. It is easy enough to see this in politics, of those who believe themselves peacemakers and agents of reconciliation actually being the dividers and creators of faction. Yet if we are not to fall into precisely the same trap, we should notice what it is we ourselves hate in individuals and groups. "Lord, is it I?" What and who do I hate? Therein lies my greatest danger, and the one I am most blind to.
It would be too strong to say that Tolkien uses the One Ring to symbolise this, but he does use it to describe and illustrate it. Frodo is unable to give up the ring even at the very beginning of the quest, though he has no aspirations to power at the time. The power of the ring to render him invisible to escape inconvenience or danger is his only temptation. Yet at the end, he has become tempted to its power and cannot throw it away. He does not put it on to escape, but to rule, like Sauron. He has become what he has hated.