My friend and I were having a very inspiring conversation on the phone last night. She was asking me what would've happened if the Ring had somehow fallen into Boromir's hands, and he had wielded it to kill off Aragorn and the rest of the Fellowship.
I answered: He goes back to Gondor, and sees his father Denethor, of course. Then, Denethor would want the Ring, and Boromir wouldn't give it up. Then one of them would die (or maybe both) and the one left with the Ring would rule Gondor. First, he'd try to get rid of Mordor, and assuming he did get rid of Sauron and Saruman, he will own ME. Then, they'll start killing Rohan, Shire, and all the other places (save Gondor). In the end, someone may cut the Ring off his finger, or ME itself will burst from environmental problems and everyone will go KABOOM!
He gets the Ring, is crazy for hatred against Sauron, so goes to challenge Sauron in Mordor. But between Sauron and a Ring-wielding Boromir, I think Sauron would definately win the duel. And well...he'd get the Ring back...
Then she asked me what would've happened if Faramir took the Ring.
I reply: faramir knows what would happen if he took the Ring, so he would not take it.
She says: then what does he know would happen?
I answer: He would not be able to resist, and he will put on the Ring.
She: But Faramir's such an honorable person, he wouldnt do bad things with the Ring, especially if he knew that the Ring was trying to tempt him.
Me: The Ring would the find more subtle ways to tempt him. If it can't use his love for Gondor, then it will use his love for his family (especially the father). If even that does not work, then it will work on his love for honor and virtue. When a person wears the Ring, I think the Ring could show you what it wanted you to see, and what it didn't want you to see it would screen from your eyes. Then it could wash most things of light from your mind.
She: Faramir would never forget the memory of beauty and good.
I: But he would be very lost if his found out that his whole idea of "good and fair" was actually all false. If everything he based his knowledge upon was challenged and turned upside down. If Manwe and Varda were slandered beyond thought, and all the heroes he'd grown up hearing about were but cowards.
She: OK, you win. Why doesn't the Ring turn traitor against Sauron, though, if it has a mind of its own?
I: It cannot turn against him, because it will be destroyed with him.
I: The Ring affects those who have desires that, no matter how twisted, are not selfish. The Ring affects those who love (or think to love) something other than themselves.