[The Saucepan Man]

Great post, Findegil. Makes perfect sense to me.

As I see it, Sauron was judging others by his own standards and ascribing to them his own motives. He assumed that those who came into contact with the Ring would inevitably attempt to use it to gain power, rather than destroy it. And this assumption was not entirely unjustified in light of the behaviour of Saruman (one of the "wise").

His fear on perceiving Frodo with the Ring at Sammath Naur is occasioned by the sudden realisation that, if someone could make it all the way to Mount Doom with the Ring without having attempted to use it to gain power, then they might just be capable of destroying it. The passage refers to him suddenly realising the "magnitude of his own folly". In other words, it only occurred to him at that moment that his assumption that anyone bearing the Ring would inevitably try to use it to gain power might actually be incorrect.

As matters turned out, he was right that (Bombadil excepted) no one could willingly destroy the Ring, but for the wrong reasons. As Findegil has pointed out, it disn't occur to him that the Ring could coerce someone to simply desire possession of it, without regard to enhancing their power, to such a degree that they would be incapable of destroying it. So, but for the intervention of "providence" he needn't have feared.