Sauron's got forces in his favor. He's got Orcs, Men...whole troops of almost every kind of race. And let's face it, they're kicking the ass of the good guys. Good guys are overpowered and dying.
Now here we have the Ring. Shiny, pretty, but why exactly would it matter if he got it back? Middle-Earth's already going bad anyway!
If you put it on, Orcs don't flock to you and say "How may I serve you, my lord?" You can't point it at people and say "DIE!" and have it happen...
Sauron's winning. Good guys are loosing.
How exactly does having the Ring give you any kind of advantage at *all*?
I feel stupid for not knowing, but it's weighing on my mind and I've got problems with not having the explaination.