At the end of ‘The Return of the King’, Bilbo, Frodo, Gandalf and others boarded a boat and left Middle-earth for Valinor.
Is there any canon explanation why they couldn’t just take the ring there in the first place and leave Middle-earth altogether? Would Sauron have gone after them? Couldn’t the elves living there safeguard it?
I do realize that without Frodo taking the ring to Mount Doom there would be no story at all, but I wonder whether or not there is any canon explanation for this.
Elrond says so in the council:
“But Gandalf has revealed to us that we cannot destroy it by any craft that we here possess,” said Elrond. “And they who dwell beyond the Sea would not receive it: for good or ill it belongs to Middle-earth; it is for us who still dwell here to deal with it.” -FotR, Book 2, Ch.2.
Basically, since Sauron made it in Middle-Earth they have to deal with it there. Additionally there is concern of it being intercepted by creatures in league with Sauron while on the sea, I seem to recall.
EDIT: As Daniel Roseman pointed out in the comments (along with a nice quote from the book), it is unlikely they would have made it even that far, considering they would have to go back on the very road whence they came, and they barely survived that (at least in Frodo's case):
'And that we shall not find on the roads to the Sea,' said Galdor. 'If the return to Iarwain be thought too dangerous, then flight to the Sea is now fraught with gravest peril. My heart tells me that Sauron will expect us to take the western way, when he learns what has befallen. He soon will. The Nine have been unhorsed indeed but that is but a respite, ere they find new steeds and swifter.' -FotR, Book 2, Ch.2.
Lord Elrond himself follows it up with the explaination why fleeing back towards the sea is such a bad idea:
'The westward road seems easiest. Therefore it must be shunned. It will be watched. Too often the Elves have fled that way. Now at this last we must take a hard road, a road unforeseen. There lies our hope, if hope it be.' -FotR, Book 2, Ch.2.
It has already been pointed out in BMWurm’s answer why neither elf nor wizard considered trying to take the ring west sensible, and that the peoples of Middle-earth would have to deal with the ring by themself, eventually, because Valar intervention would not be an option: “And they who dwell beyond the Sea would not receive it: for good or ill it belongs to Middle-earth; it is for us who still dwell here to deal with it.” Still, this doesn’t explain why that is the case — and the reason for it is, in my opinion, is the real answer and the most important fact, being directly related to the entire genesis of Middle-earth.
As we have already seen in the past, each Age was related to one “scale” of epic conflict — while the First Age was an obvious “Epic-est Fight of Valar & Elves vs Melkor”, with the greatest scale of both conflict and damage, the Second Age was “Epic-er Fight of Elves & Humans (Númenóreans) vs Sauron”; on the other hand, the Third Age was “Epic-ish Story of Couple of Battles of Humans & what’s left of everybody else vs what’s left of Sauron” — it’s the obvious road to the concept of the Dominion of Men that would follow in the Fourth Age. That was the plan of Eru from the very beginning, and, obviously, it required Men to deal with the remnants of the past to forge their future, one way or another. As such, while divine intervention was not only possible, but happened as a straight fact (Great Eagles' help, Gandalf being reborn, etc.) — it was Men (well, in a strange alliance with all the remaining sentient races of Middle-earth) who finally defeated Sauron (in the military sense) — and the Hobbits who won the fight in the broader sense — as such, fulfilling their destiny by setting their future. Yes, it was their destiny to create their destiny — as opposed to the Elves, obviously.
Also, note that this is strictly parallel to the storytelling aspect of any epic work — signifying that it’s not only an in-world reason, but an artist’s reason too — it happened the way it should happen to make the most of the story — because the story was meant to go the most expressive way (see other epic works, from Homer for example). Also, see Tree and Leaf — as JRR Tolkien explains this concept there to some extent, being parallel to Jesus Christ’s death — it has to happen, because it’s for greater good and because God has planned it this way. To extrapolate (since Valinor was a “heaven” of sorts from Human point of view) — asking The Ring (the source of sin) to be taken to Valinor was similar to asking God to take away sin/plague/some source of evil from Earth to Heaven — it was impossible, because it would, in a way, rob Man of their destiny to forge their free will.
Therefore he willed that the hearts of Men ... should have a virtue to shape their life, amid the powers and chances of the world, beyond the Music of the Ainur.
NB: if somebody would be so nice as to provide me with some more source citations (I’m too lazy/busy to dig for them) to back it up, I’d be very grateful.
Valinor was not an option, because Eru explicitly made it Man’s sole choice/possibility to be able to forge their destiny by defeating Sauron in the Last-est Alliance of Middle-Earth — bringing The Ring to Valinor and throwing the potato at Elves/Valar was thus not an option.
It would not make the problem (Sauron) go away. Even without the Ring, Sauron was becoming too powerful and was ready to conquer Middle Earth. And as others have said, The Valar would not receive the Ring. Destroying the Ring was really their only option.
This was the conclusion that was reached at the Council of Elrond, after they debated every option.
Also, since Sauron is a Maiar spirit who sided with Melkor (a Valar - god - who turned bad in ages past but was finally defeated by the assembled forces of the rest of the gods). One might argue that Sauron would simply go to Valinor as well and the fighting would spread to there.
The Valar and Maiar, had come to Middle-Earth at the end of the First Age, to defeat Morgoth, the original Dark Lord, in the War of Wrath.
After the First Age, the Ainur swore to never again, directly interfere with Middle-Earth.
This oath, was the reason why they sent the Wizards.
