Sauron's battle strategy

[Farael]

Originally Posted by The Might

But as I said...did it really matter to him what he attacked first?
No.
Because he was 100% that nobody would even think about destroying the Ring, but would rather try use it against him. So from his point of view no matter what his enemies tried, he would still have defeated them eventually.

Actually, it did matter. I can't remember the exact quote, but we know he was still able to feel fear. He feared that, if given enough time, Isildur's heir would be able to learn how to wield the Ring appropiately, and summon a host large enough to make things very hard for Sauron. Not to mention that if someone such as Saruman would have gotten the Ring, things would've looked rather bleak for Sauron.

Therefore, it did matter who he attacked first. He believed Aragorn to have The Ring. First of all, I'm sure he feared that the heir of Isildur might be able to overthrow him, like Isildur did in the past. Second, he knew that while Aragorn had it, it was the "lesser evil" of the other possibilities. If Saruman or Gandalf had laid their hands on it, he would've been in trouble.

That's why Aragorn's looking into the Palantir is such a crucial moment in the books. IF he had not done so, Sauron might've kept his forces in reserve for a longer time and Frodo would have been found. Furthermore, if Aragorn had not tried attacking the Black Gate, the hosts that were camped across the plains before Mt. Doom would've never moved and once again, Frodo would have been caught.