Nobody in Middle Earth or on these boards has asked the crucial question: What would have happened in the history of the Ring if Isildur had survived?
Isildur was certain to become corrupted by the Ring, and he was already head of a major, practically world-wide empire (encompassing the kingdoms of Gondor and Arnor). Do I smell ascendent Dark Lord? It wouldn’t have taken him too long to become as powerful as Sauron, and eventually just as evil.
Would the Elves eventually have to make war against Men as they were led by a new Enemy? Would the Nazgul have flocked to Isildur’s aid? Two of Middle Earth’s other three ringbearers, namely Elrond and Galadriel, had to be keenly aware of these dangers. It was in their explicit INTEREST to have NOBODY controlling the One Ring, so that they would be free to wield their own.
It SEEMED to be just happenstance that Isildur was caught with his pants down some time after the final showdown with Sauron. Indeed, he had already made it back home to Gondor, bringing the Ring with him, of course, before venturing out again to Gladden Fields with only a token contingent of guards.
So here’s my theory: Elrond knew what would happen to Isildur and the dangers of a new Dark Lord arising, and a disasterous new war that the Elves and free Men might not win this time. Elrond was right there at the beginning, and could see the corruption already working on Isildur as he claimed the One Ring for his own. However, he could hardly take the Ring from Isildur by force in front of all of those Men arrayed for battle. Nor could he assail Isildur once he had returned to Minas Tirith.
Furthermore, that “attack by Orcs” at Gladden Fields always struck me as just a little too neat–the newly crowned King of the most powerful kingdom in the world just happened to be wandering around undefended and far away from his kingdom–BUT not too far away from Lorien and the wily Lady of the forest.
So. The Elves somehow lured Isildur out on a lightly defended expedition and then attempted to seize the Ring by force. They shot him in the river when he tried to get away, and the Ring was lost, leaving the Elves to sweat it out for another couple of thousand years.
All this casts a new light on Elrond’s subsequent behavior, doesn’t it? All that business about protecting Isildur’s heir. And it would have been the right thing for them to do, at least in their own eyes, a fact that further persuades me that this is a viable theory.