Why did Sauron need ring?

[Raynor]

Originally Posted by Sauron the White

Does anyone here seem to subscribe to the idea that IF Sauron did get the ring from Frodo then he could have somehow increased his might to take over Middle-earth under his rule as many seemed to fear?

Since it doesn't look seem like this quote has been brought before:

Originally Posted by Last debate, RotK

Concerning this thing, my lords, you now all know enough for the understanding of our plight, and of Sauron's. If he regains it, your valour is vain, and his victory will be swift and complete: so complete that none can foresee the end of it while this world lasts.

Originally Posted by Neithan Tol Turambar

Close to half the number of all the Elves and Men of the West who could wield blade died in that war.

Hm, is there some evidence in that regard?