Why did Sauron need ring?

I think the time of the Lord of the Rings was actually a pretty troublesome time to begin with.

I'm not sure what Tolkien says or even if does say anything about recent history in the third age(famines, wars, rebellions?) but it seems to me everyone has been having problems and no one has been doing to well(examples? the second Khazad Dum...).

The power of the ring, though, is unbroken, so I can understand the fear of not just Sauron, but anyone getting the ring! But Sauron in particular since it's easier to direct fear at him than at the ring, since you would have to fear yourself as well.