[the phantom]

The character who would go and wield the Ring would take it freely and therefore without influence of the Ring.

Look at the temptation of the ring again. One of the biggest signs that someone was corrupted by the ring was that they desired it. People who managed to avoid its corruption wanted nothing to do with it (Gandalf, Elrond, Faramir). If they had a desire for the ring, then they were giving into the ring's temptation of power, plain and simple.

First off, remember that the Ring was not created with the purpose of corrupting its bearer in mind.

You think this even though Tolkien said "it was part of the essential deceit of the Ring to fill minds with imaginations of supreme power." It sounded planned.

I, for one, do believe that Sauron put some fail safes on the ring. Remember, he wasn't all crazy and nihilistic like his master, he was cunning, though I recall Tolkien writing that he became less so in his later years after serving himself for so long.

It seems to me that giving up the Ring is the one thing that the Ring will never allow you to do

Unless it suits its purpose. If it has enough of a hold it could make its owner do (or trick them into doing) whatever it wanted.

As I said, I do not unfortunately have the Letters. Does anyone recognize the passages that I am referring to?

I know the very thread of which you speak. Yes, I remember what Legolas posted. It was this-

Of the others only Gandalf might be expected to master him – being an emissary of the Powers and a creature of the same order, an immortal spirit taking a visible physical form.

Of course, it doesn't say Gandalf would master him. And what does he mean by "master" anyway. Does he mean that he could defeat his forces, or somehow break Sauron's tie to the ring, or what?

I think there's still plenty of wiggle room for my "the ring plot was a perfect plan" theory.