Supposed Sauron hadn’t made the One Ring and created the instrument of his own destruction. Could he have gained the power necessary to take over Middle-Earth anyway? At the time, he was sorta weak and needed the One Ring to control the other rings I think. But by the time of the LOTR events, he was basically the most powerful being in Middle-Earth. If he hadn’t made such a vulnerability, wouldn’t he have triumphed eventually?
Yep. When Aragorn & Co. were arrayed in front of the Black Gate, without the destruction of the One Ring pulling the ladder out from under Sauron, the bad guys would have stomped the good guys flat, and they were the last coherent force opposing Mordor.
However, if he hadn’t made the One Ring in the first place, he might not have been able to amass such power in Mordor (the Ring allowed him to bind the Nine more fully to him, and they were pretty powerful generals to have around). Ultimately, the fact that the One Ring was driven to return to him caused his downfall. If it had just fallen into the river and been lost forever, everybody in Middle Earth would be black & spiky.
Sauron was incredibly powerful before he forged the One Ring. His primary adversaries, though at the time they didn’t recognize Sauron for what he was, were the Elves. He played on the deep desire the elves had to preserve and heal the hurts in Middle Earth. He counted on them doling out the 7 and 9 to various elf lords and by wielding the rings he could control them through the One.
The One Ring provided access to a power in *excess *of what Sauron’s nature would allow. He needed that power to dominate the elf lords.
Of course once they removed their rings he smashed Eregion, took and dispersed the 7 and 9, drove the elves back to Lindon and generally stomped around ME until the Numenoreans showed up.
In “Morgoth’s Ring”, (JRRT’s notes and draft manuscripts relating to M-E), there are some hints and indirect speculation that lead some to infer that the wielder of the One Ring could use it to tap into the corrupt power that Morgoth infused into Arda itself at its creation (aka “The Morgoth Element”.)
From: The Morgoth Element.
My understanding is that without the One Ring the power of the other Elven rings would be too much for Sauron to overcome. The forging of the One Ring allowed him to link the rings together and diminish the control of the others. The nine given to men he was able to holey corrupt to his will and the dwarven seven were basically nullified. The three elven rings (and their bearers) were strong enough not to be corrupted or subsumed but even they had to go into hiding to protect them.
The 7 and the 9 were meant for the elves. Sauron was quite disappointed that they did not fall for this trap. It would have negated a lot of elven opposition to his plans if it has succeeded, causing the elven wearers of those 16 rings to come under his sway.
When that failed, he handed them out to men and dwarves, as an improvised Plan B. It was far less effective than his Plan A would have been, had the elves taken the bait.
The 3 elven rings (forged without Sauron’s knowledge but using his techniques) were wild cards, but since they were not meant for power, aggression, or dominion, they did not provide the elves with serious opposition to Sauron’s aggression. It did enable them to resist it more effectively, however. It reduced the damage the elves took from Sauron’s attacks, but it didn’t enhance the ability of the elves to harm Sauron.
If Sauron had not forged the One Ring (and given himself an Achilles Heel), I suspect he would inevitably been able to wait for the waning of the elves and the departure of those most powerful of the Eldar over the sea, and then corrupted men and forged an empire spanning Middle Earth. But pockets of resistance would have continued, and he never would have been able to corrupt all Arda without the One Ring (which I believe was his ultimate goal in forging it.)
I’m going to come down as the dissenting voice here. First of all, I think it’s a mistake to think of The One as strictly an “Achilles heel” or even strictly as a means of controlling the other rings. Sauron with The One was more powerful than Sauron before the ring was forged. I can’t provide a supporting cite, per se, but that seems to be primary function of the Ring - the stronger you are, the more it increases your power. There’s no reason to think that Sauron is somehow exempt from this.
Now we add on the fact Sauron loses repeatedly to the men of Numenor during the second age, we have to question - could he even have overcome the Elves in Eregion had he not weakened them with the whole Rings scheme, and created The One to bolster himself? Certainly, it would have been a much nearer thing, or why bother with the whole setup in the first place? Sauron has demonstrated that while he can be crafty when it’s to his advantage, he has no problems just using overwhelming force if he’s got it.
I think the very fact that he bothered to create The One means that he certainly saw advantages to it, and I think everything we find out about it leads us to believe that it magnified his powers. Certainly, it was helpful to him even AFTER he lost it, since the foundations of Barad-Dur were built using its power, and thus could not be removed by Gondor when the Last Alliance crushed him.
I think it’s also unreasonable to assume that subjugation of 9 human kings didn’t expand his influence into the East and the South, which provided a nontrivial part of his armed might in the 3rd age. And that’s discounting stuff like the power of The Nine themselves (especially The Witch King).
I think we are forced to assume that The One provided tremendous benefits to Sauron that he would not otherwise have had.
I am certainly on board with that; anything that allowed him access to more power (as implied in my first post in this thread) is a definite benefit. The forging of the One Ring gave him great rewards and access to greater powers with very little risk.
But not no risk. And even then, it took a eucatastrophe to overthrow him.
I agree with Airk.
Isildur would have been able to defeat Sauron even if (or perhaps more easily if) Sauron had never forged the ring.
Without the ring, Sauron would have been dead right there at the hands of Isildur.
So the ring is an Achilles heel from the LOTR trilogy’s perspective… but without the ring, Sauron would be just like Morgoth: nothing but an ancient story for Bilbo to be blissfully unaware of as he sipped his ale.
Instead of LOTR, we’d have had
“Chapter 1. Bilbo buys some dodgy meat in Bree.”
“Chapter 2. In which Bilbo runs out of tea.”
“Chapter 3. Bilbo trades witty barbs with his relatives.”
Yes! Finally, the next trilogy! 
If Sauron had not created the One Ring, he would have died when Numenor sank.
Right. He only “lived” on as his lifeforce was tied to the Ring.
Untrue. He is an Ainur, and cannot be slain. Even now (well, in the imaginary M-E now) Sauron’s spirit still exists, just stripped of power (same for Saruman). Had his body perished without having made the ring, he still could have re-created it, perhaps even in a fair form. The Valar and Maiar changed bodies like others changed clothes.
The Istari were special cases in that they were actually incarnated as men (albeit with loooong lifespans). They felt the pains of mortality and were greatly constrained by their fleshly forms. But the death of the body was not the end of them.
Melkor still lives too, just locked out of Arda.