The key quote from Tolkien that answers this is contained in Letter 246, with my added emphasis: > It was part of the essential **deceit** of the Ring to fill minds with **imaginations** of supreme power. This implies that the Ring is useless to anyone but Sauron, but it tempts you into thinking it's a source of power, and in that way it gets you to wear it, and so gains control over you. ---------- In order to proceed in an investigation of this, and how to reconcile it with other statements made by Tolkien we must first establish a baseline that we're going to work from: - It is accepted that the Ring gave some degree of "power" to Isildur, Gollum, Bilbo, Frodo and Sam, in the form of invisibility, longevity and an occasionally enhanced presence. - Sauron was the maker of the Ring; he originally made it for his own use, and his own use only; he certainly never intended it to be used by anybody else, and he had no requirement for any of these three (as he already possessed them due to his nature as a Maia). - Therefore these three "powers" were not an intrinsic property of the Ring intended by it's maker, but rather *side-effects* of it being used by a mortal. - And these "powers" are actually quite minor compared to those possessed by a Maia. - There are different kinds of "power"; these minor (by comparison) "powers" are one kind that are available to mortals as Ring-bearers, but the power to raise armies, control others, defeat Sauron and rule Middle-earth is a completely different kind altogether. ---------- Now let's look at what Tolkien says about the Ring, quoting from the same source as Shamshiel's answer: > But even if he did not wear it, that power existed and was in 'rapport' with himself: he was not 'diminished'. Unless some other seized it and became possessed of it. If that happened, the new possessor could (if sufficiently strong and heroic by nature) challenge Sauron, become master of all that he had learned or done since the making of the One Ring, and so overthrow him and usurp his place. Here it's important to look at what Tolkien says, and *only* at what Tolkien says. Here's what he does *not* say (and note the emphasis): - Some other person is *controlling* the Ring. - That other person is *gaining power* from the Ring. - That other person is *using that power* against Sauron to defeat him. And here's what he *does* say (emphasis again): - Some other person has *claimed ownership* of the Ring. - That other person has, through their own "sufficiently strong and heroic" nature, succeeded in *taking that ownership* of it from Sauron. - And Sauron as a result *is diminished and can be defeated* by the unenhanced other person (again, if "sufficiently strong and heroic"). This is an important but subtle distinction. In the first case the other person is using the Ring to give themselves a "level up" against Sauron, to boost their own power and defeat him that way -- but *that's not what Tolkien is saying*. In the second they're not doing this; the power in the Ring is quite useless to them but *by being able to deny it to Sauron they diminish him* and hence (though their own natural but unenhanced strength) are able to defeat him. As for "become master of all that he had learned or done since the making of the One Ring" - Tolkien does not actually define what he means by this. But since the greater part of Sauron's power is in the Ring, it seems reasonable to suggest that this "mastery" actually belongs to the Ring itself rather than to the wielder (hence "since the making of the One Ring"), who only obtains the "mastery" by proxy. > But the Ring and all its works would have endured. It would have been the master in the end. ---------- Now we'll continue by looking at some other sources. First of all, the words of Galadriel: > Before you could use that power you would need to become far stronger, and to train your will to the domination of others. These seem to indicate that one could use the power of the Ring, but there are two traps being set for the careless reader here. The first one I've mentioned already: > It was part of the essential **deceit** of the Ring to fill minds with **imaginations** of supreme power. And the second is mentioned elsewhere by Tolkien with reference to a different character in a different situation, but must surely also apply here: > Treebeard is a *character* in my story, not me... So what we actually have here is Galadriel being *deceived* by the Ring into thinking it can be used, and remembering that she is a *character* in the story, not Tolkien himself, her words must only be read as being *in-character* - they shouldn't be interpreted as Tolkien describing the way things are. The same can be said of anyone else who describes using the Ring's power in a similar situation: Gandalf, Boromir, Denethor, even Elrond when he says "I will not take the Ring to wield it". ---------- I'll round things off with some other observations, also from Letter 246. First of all Tolkien equates taking control of the Ring with *the Ring taking control of you*: > He needed time, much time, before he could control the Ring or (which in such a case is the same) before it could control him. Then he establishes how difficult it is to face Sauron, even if you have tried to claim the Ring (and indicating that the Ring has no power over Sauron too): > Sauron would not have feared the Ring! It was his own and under his will. And then he reiterates that the upper hand in a contest with Sauron does not come from your possession of the Ring, but rather from Sauron's lack of it: > On one side the true allegiance of the Ring to Sauron; on the other superior strength because Sauron was not actually in possession. ---------- In summary - the answer is "no", the Ring *wouldn't* work for anyone else in the way they *think* it would (by granting them additional power or by being able to be used as a weapon), because remember: > It was part of the essential deceit of the Ring to fill minds with imaginations of supreme power. But "yes", it *would* work by causing Sauron to become diminished, provided they were strong enough to be able to take and retain control of it; they would remain limited to their own native ability in any contest against Sauron, however.