so - How would the story have played out with Sam as ultimate rign-bearer?
I’d guess that Sam could have tossed the Ring into Mount Doom instead of having his finger bitten off.
It’s difficult to say. Sam was able to resist the lure of the ring and return it to Frodo. That doesn’t necessarily have meant he’d been able to do so if he’d had to cross Gorgoroth by himself and then carry it into the cracks of doom, where the power of the ring was at it’s greatest.
Didn’t he pretty much come out and say it? Frodo could carry the ring and he could carry Frodo but he couldn’t carry the ring by himself.
No, that was because taking the ring would have driven Frodo mad. Remember Frodo’s reaction when Sam offers to share the burden of the ring after rescuing from the tower of Cirith Ungol. Frodo calls him a thief, although he immediately repents his words, which both Frodo and Sam understand are due to the ring’s influence on him.
“I may not be able to carry the ring, but I can carry you”
As the other poster said - it was due to it being “frodo’s burden” -nothing to do with wieght or ability or strength of charector - he did carry it for the time that he thougth Frodo was dead, and was able to return it.
It’s Sam. He’d wander aimlessly for a while, get hungry, then get dry gulched either by Smeagol or a platoon of orcs. Either way Sauron’s got the ring back in time for second breakfast.
I think he was only able to return it to Frodo because he loved Frodo, and because he was Frodo’s loyal servant in some feudal relationship that I am not able to understand but that reminds me Wimsey-Bunter, commanding officer and batman in a score of British novels. If he were on his own, without helping Frodo as a motivating force, I think he would succumb to despair and give up. Or he’d put it on to help himself get to the Cracks of Doom and be found immediately, as he didn’t have the desire for power or the will to dominate required for mastery of the ring.
Does anyone remember Sam from the Bakshi film? They only filmed half, but Sam was portrayed as a bit mentally challenged. That Sam could have simply tossed the ring into the cracks without a first thought.
But Sam in the books is NOT mentally challenged, just not on the same social-economic-cultural level as Frodo. so let’s stick with the books. - Sam knows all the ring’s backstory, knows the importance of the mission. He has just won smackdowns with Gollum and Shelob. Is there any reason to believe Sam could not have made it to Mount Doom & destroyed the ring? I think he could, but his story would not have been as interesting as Frodo’s. Frodo bore the ring longer, it was a harder job for him. Frodo shows mercy to Gollum. Frodo becomes a pacifist, and has to leave Middle Earth due to his guilt and PTSD - don’t see those happening to Sam.
I think its implied pretty heavily that no one can purposefully destroy the ring. Frodo can’t, Isildur can’t, I don’t really see any reason to think Sam could’ve. Had Sam carried on alone, Gollum would’ve presumably ambushed him on the way and either taken the ring himself or been killed by Sam, leaving Sam to make it to Mt Doom but unable to take the final step and toss the ring in.
I disagree, I think Sam is the only character presented in the books that could do that. Sam only wanted two things, to serve his friend and master, Frodo and to settle down to a nice Hobbit life with Rosie Cotton. He was the one character that the ring had nothing to offer. All of the others who come into contact with the ring are after power or adventure or riches. None of those thing appealed to Sam.
The downside for Sam, is that he is someone that the ring would have done its damnedest to get away from at the first opportunity.
He wasn’t, but he certainly thought he was. I mean, he’s even named “Halfwit, son of Stay-at-home”.
And it is notable that he alone of all beings of Middle-Earth was able to give up the Ring freely and without coercion, something that the Wise would have thought impossible. If anyone could have thrown it into the Crack (a point which is admittedly unlikely), it was Sam.
It’s the good master/dutiful servant relationship, which seems rather odd to us. Many British people of Tolkien’s era really did think like that. Despite being a lifelong supporter of the labour party, my grandfather has a deferential attitude to those he perceives to be his social betters.
I tend to agree that Sam could not have resisted the ring all the way across Mordor on his own. Frodo couldn’t, and Gandalf thought him “the best Hobbit in the Shire.” I do wonder if Sam could have destroyed the ring if it had come into his possession at the cracks of doom. However, it’s hard to see how that could have happened. Frodo couldn’t have given it to him, and Sam probably couldn’t have taken it.
Frodo spends half the series offering to give the ring to pretty much everyone they run across (Gandalf, Elrond, Galadrial, Tom B.). It doesn’t seem to be that unusual, at least before the ring really gets its hooks in.
How about Shelob tossing it into Mt. Doom? Or would she have become “Shelob of the seven legs?” 
Well that’s false. I don’t have the books in front of me, but I remember a specific passage where Sam has a vision of himself wielding the Ring, and he’s master of a garden paradise. No one’s immune.
I think if Sam had been able to make it that far by himself (which I agree is very unlikely), he probably couldn’t have ditched the Ring as planned but he might have thrown himself in with it.
In despair over Frodo’s death and the nightmare environment of Mordor (most horribly manifest in its heart at Orodruin itself), and probably also in terror of orcs or worse that would most likely have been hot on his trail if not actually breathing down his neck by that time, I can see Sam forgetting starlight and the scent of garden earth and rain in the Shire and just grimly staggering to the chasm’s edge and then taking the last step. Faithful to the last, but with hope finally dead.
As it was, it was simple fortune that destroyed the ring. In the book anyway, Gollum takes the ring and while dancing and gloating, simply steps off the ledge by accident. Without Gollum, the ring wouldn’t have been destroyed.
'Deserves it! I daresay he does. Many that live deserve death. And some that die deserve life. Can you give it to them? Then do not be too eager to deal out death in judgment. For even the very wise cannot see all ends. I have not much hope that Gollum can be cured before he dies, but there is a chance of it. And he is bound up with the fate of the Ring. My heart tells me that he has some part to play yet, for good or ill, before the end; and when that comes, the pity of Bilbo may rule the fate of many - yours not least.
Sure, the Ring tried to tempt Sam, and it worked with what it had available, but Sam was able to immediately recognize the temptation as absurd. The Ring wasn’t able to offer anything Sam wanted, just something that vaguely superficially resembled something that Sam wanted.