It’s all in the link I gave: Center for the American Idea
And I must apologize for consistently misspelling TolkIEn’s name. :smack:
Well among other things, Sauron would have instantly gained mastery over the three Elven Rings, their wearers, and all the works done with them. To quote:
“Those who made them did not desire stength or domination or hoarded wealth, but understanding, making, and healing, to preserve all things unstained. These things the Elves of Middle-earth have in some measure gained, though with sorrow. But all that has been wrought by those who wield the Three will turn to their undoing, and their minds and hearts will become revealed to Sauron, if he regains the One. It would be better if the Three had never been.”
Here’s a nice little table explaining Sauron’s power, with and without the ring, along with the ring’s power, with and without Sauron. It’s more complex than it would seem at first glance.
And The Last Alliance of Elves and Men were able to eventually defeat Sauron’s forces, and throw down Sauron himself because the combined might of the Elves was far vaster in the elder days.
Besides, despite what the movie shows, it was not a lucky fluke that defeated Sauron. Gil-Galad and Elendil both gave their lives to overthrow Sauron, enabling Isildur to cut the ring away while Sauron was immobilized by two of the mightiest Children of Iluvatar to then walk Middle-Earth.
Oops, forgot the table
And keep in mind that the three bearers of the Elven Rings were Galadriel, Elrond, and Gandalf himself. Their wills would have immediately become Sauron’s, and THAT would have been a killing blow for any hope of resistance.
What’s always fascinated me is the fate of the Seven Dwarven Rings (seems like if the orcs got hold of them, they’d get them to Sauron posthaste,) and all these other Rings of Power that Gandalf mentioned in FotR. I’ve always wondered if maybe there were one or two stashed away in the trolls’ hoard.
But they would not have been enthralled to Sauron. He would have discovered their secrets, their plans. Just like he did back in the second age, when he first forged the One Ring. When he put on the ring, the elves knew at once how they had been deceived, and they all removed their rings! Celebrimbor then gave one ring to Galadriel and sent the others to Gil-Galad. Sauron didn’t know where the rings had gone. But he laid siege to Eregion, slew Celebrimbor, and seized the other rings, which he passed out to men and dwarves.
Certainly it would have been a disaster for Sauron to learn the hearts and minds and plans of Elrond, Gandalf, and Galadriel. But their wills would still have been their own.
Also, if Sauron had The One Ring, whenever he went to Burger Lord for lunch, he would just have to show it off and he’d get everything up-sized for free. 
Anyhoo…
Sauron recovered four; the other three were eaten by dragons (along with their wearers). Tolkien mentions this in passing somewhere, I believe in a letter. The one Dwarf-ring for which we know the ultimate fate is Durin’s, which was passed down through Durin’s heirs – it was the last of the Seven to remain free. Thrain II, father of Thorin II Oakenshield, was captured and held in Dol Guldur, and the ring stripped from him – Gandalf encountered him there. (This is recounted by Gandalf in one of the narratives in Part III of Unfinished Tales.)