Hi Beech27,
If the Ring is tempting Frodo, then I agree that this does not contradict Catholic orthodoxy.
What if the Ring is not tempting Frodo, but compelling him?
I think that the passage at the Crack of Doom can be read either way. We get no explanation in this passage as to why Frodo decides to claim the Ring rather than destroy it. We know (from 'Sauron Defeated' in THOME) that Tolkien at one time drafted this scene with an explanation which involved Frodo deciding to seek power and domination, but this was rejected in the final version.
If we don't get any explanation in the passage, but we want to figure out WHY Frodo claims the Ring (a fairly central event in the book), then, it seems to me that all we have to go on is what we know about Frodo and the Ring from earlier in the book.
We have almost never seen any evidence that Frodo is tempted, or could be tempted to claim the Ring in order to get power and domination. The closest he comes to that is when he thrice threatens to use the Ring to dominate Gollum, once outside the Black Gate, after Smeagol has begged Frodo to give him back the Ring rather than take it into Mordor, again, at the pool in Henneth Annum, to get Smeagol to leave his fish and come, so he would not be shot by the Rangers, and finally, on the slopes of Mt. Doom, occasioned by Gollum attacking and trying to seize the Ring. Grander temptations of power and dominance would be quite alien to anything we have seen of Frodo so far. When Frodo has put on the Ring, or been tempted to put on the Ring, his usual temptation, or impulse, is to hide or escape, not to dominate.
The main effect of the Ring on Frodo (and on Isildur, Gollum, Bilbo, before him, and even to Sam) is to make itself 'precious' to its holder. Frodo's possessiveness towards the Ring seems to grow over time. It starts early. In Bag End, when Frodo hands the Ring to Gandalf, "slowly....It felt suddenly very heavy, as if either it or Frodo himself was in some way reluctant for Gandalf to touch it." Frodo does hand the Ring "at once", to Tom Bombadil, but he did it, "to his own astonishment", as though he was surprised at how uninhibited he felt in doing so. Frodo offers the Ring freely to Galadriel, but we don't know how readily he would have gone through with his offer had she accepted. Then he resists giving the Ring to Boromir, though more because it is a bad idea than through possessiveness.
However, his threat to dominate Gollum with the Ring, though couched in concern for Gollum's 'danger', may be indicative of growing possessiveness. "But I warn you, Smeagol, you are in danger.... Give it back to Smeagol you said. Do not say that again!... The desire of it may betray you to a bitter end. You will never get it back. In the last need, Smeagol, I should put on the Precious; and the Precious mastered you long ago. If I wearing it, were to command you, you would obey, even if it were to leap from a precipice or to cast yourself into the fire. And such would be my command." Frodo calling the Ring 'The Precious', even in imitation of Gollum, may also indicate that he is beginning to think of it that way himself. If the Ring could 'master' Gollum, why couldn't it 'master' Frodo as well?
Then, we have the passage in the Tower of Cirith Ungol, between Frodo and Sam. Even Sam feels a touch of possessiveness towards the Ring. "Now it had come to it, Sam felt reluctant to give up the Ring...", which he rationalizes (in a 'Ring induced rationalization' kind of way) as, "...and burden his master with it again."
Frodo's response seems to indicate that possessiveness towards the Ring has him firmly in its grip. "'You've got it?' gasped Frodo. 'You've got it here? Sam, you're a marvel!' Then quickly and strangely his tone changed. 'Give it to me!' he cried, standing up, holding out a trembling hand. 'Give it to me at once! You can't have it!'" Sam replies, "...'If it's too hard a job, I could share it with you, maybe?'" "'No, no!', cried Frodo, snatching the Ring and chain from Sam's hands. 'No you won't, you thief!'"
So, WHY does Frodo say, "I will not do this deed," at the Crack of Doom?
I think the most supported readlng is because the Ring has become too 'Precious' for him to destroy. (Though a case could be made for Frodo being tempted and corrupted into a desire for domination through his three threats to Gollum). Frodo groped for the tongs to fish the Ring out of his little fire in Bag End, after Gandalf threw it in. Is he really capable of throwing the Ring into the Fires of Doom now, when the possessiveness has grown much greater?
But, is Frodo tempted to feel possessive of and protective towards the Ring. Or, does the Ring compel its holders to feel possessive of it?
We can read Frodo's refusal to destroy the Ring as caused by the temptation to possess it, or by the compulsion to possess it. When Frodo says, "The Ring is mine", is Frodo claiming the Ring, or is the Ring claiming Frodo?