[Gurthang]

I believe what the phatom was saying was that Sauron could not be defeated in spirit, but only in body. At the fall of Numenor Sauron lost his body the first time, so that he could never again appear fair to man. He lost another form after the seige of Bara-dur, at which time the ring was lost. The curcumstances are quite similar, with the ring being the largest difference.

Sauron poured so much of himself into the ring, that he had to have it to take physical form. Any body he took could still be destroyed, but he needed the ring to make another one.

But back to the true question. I believe that Sauron had to make the ring to rule the world. Otherwise he never would have corrupted the kingdoms of man. But he poured too much of his power into it, and it created the weakness that became the hope of the battle.