[The Squatter of Amon Rûdh]

I have to concur with that opinion. It was utterly beyond Sam's power to make Sméagol into Gollum, but his quite natural suspicion and distaste for him certainly tipped the balance at that critical moment. I usually bear in mind the road that Sméagol had travelled before Frodo and Sam met him. Sam knew about many of his actions and suspected a great deal more. He had overheard the conversation in which Gandalf said

The Wood-elves tracked him first, an easy task for them, for his trail was still fresh then. Through Mirkwood and back again it led them, though they never caught him. The wood was full of the rumour of him, dreadful tales even among beasts and birds. The Woodmen said that there was some new terror abroad, a ghost that drank blood. It climbed trees to find nests; it crept into holes to find the young; it slipped through windows to find cradles.

Sam may not have understood much of what Gandalf said about the tragedy of Gollum's position, but he would have understood the dark hint about some of the things that he was prepared to eat. Very few people find it easy to love or forgive those who prey on children, and Sam is not very good at hiding his feelings.

Perhaps Sam's motivations can be better understood if we consider this passage from Tolkien's essay On Fairy-Stories. He refers (as does G.K. Chesterton, whom he quotes) to children; but the pivotal factor is innocence, which is a natural Hobbit quality that Sam possesses in great measure:

Chesterton once remarked that the children in whose company he he saw Maeterlinck's Blue Bird were dissatisfied 'because it did not end with a Day of Judgement, and it was not revealed to the hero and the heroine that the Dog had been faithful and the Cat faithless', 'For children,'he says 'are innocent and love justice; while most of us are wicked and naturally prefer mercy.'

To put this into the context of the story, Frodo has experienced the power and temptation of the Ring, and so wants to be merciful; but Sam has not, and desires 'justice'. 'Justice', in this case, being that the 'wicked creature' should not enjoy such complete trust as he, who has earned it. I have no doubt that his suspicion is tempered by jealousy, but it is the jealousy of one who has earned a position of trust and sees another apparently granted the same privilege without being required to earn it. He cannot see the difference between Frodo's patience and understanding with Sméagol and his utter faith in his devoted servant. Once he has experienced for himself the corrupting influence of the Ring, however, he comes to understanding, tragically too late.

He himself, though only for a little while, had borne the Ring, and now dimly he guessed the agony of Gollum's shrivelled mind and body, enslaved to that Ring, unable to find peace or relief ever in life again. But Sam had no words to express what he felt.

I find it interesting to consider Sam and Gollum as opposing aspects of Frodo's personality: the uncorrupted Hobbitry of Sam versus the often unwilling corruption of Sméagol. Frodo shows aspects of both personalities during the Ring-quest, and he is always cast in the role of mediator between them. I'm curious to know what others think about this.