Regarding Boromir... I considered your question all weekend long. Did Boromir intend to take ring the whole time, or did he fall off the wagon?
In the Two Towers, when Sam is talking to Faramir in the chapter "Window on the West", Sam says about Boromir. "I watched him from Rivendell onward and it was clear that he watched my master. In Lorien, I became convinced he would take the ring."
Also, Faramir is not surprised that Boromir made a play for the ring.
In Return of the King, when Faramir returns and Denethor finds out that he did not take the ring when he could have, Denethor said that Boromir would have brought him the ring. In fact, Denethor fully expected Boromir to bring him the ring.
And lastly, Gandalf tells Denethor that he did not trust Boromir.
So, it is my contention that Boromir planned to take the ring the whole time... to use the ring as a weapon for the defense of Gondor.
Nice case you make there. I almost believe it. But not quite. Obviously, nobody completely trusted Boromir. But that isn't the question at hand. Did he INTEND to take the ring all along? is what's before us. I refer you to "The Breaking of the Fellowship.": "What have I said?" he cried. "What have I done? Frodo! Frodo!" he called. "Come back! A madness took me, but it has passed. Come back!" Now I've read this thing 15 times over the years, and it has never ocurred to me that he was lying when he said this. From my point of view a madness DID take him: the same madness Frodo fears will overcome all of his companions (granted, this is more explicit in the movie than in the book). To me Boromir, throughout FOTR, is a decent man struggling with a simmering internal debate, not a devious, consciously scheming plotter. In any case, thanks for getting back to me. I always prefer a conversation to a hit-and-run argument. And you're welcome to disagree. As long as we're both buying tickets, P.J. will be happy. :)