sauron winning?

[Inziladun]

Originally Posted by Morthoron

In any case, the thing everyone seems to be missing is that the Valar would not or could not have sent an army if Sauron was victorious at the end of the 3rd Age. After Eru destroyed Numenor and caused the reshaping of the world, there was an obvious prohibition on the Valar offering such overt assistance to Middle-earth; which is why the Istari were sent to aid the Free Peoples rather than Eonwe and a heavenly host.

In keeping with the idea that Sauron's Third Age power was a significant step down from that which he possessed in the days of the Last Alliance, the Valar probably perceived there would be no need for another deus ex machina in the form of an army from the West to put Sauron down for the count.
During the Second Age, the Eldar and Dúnedain had been able to defeat Sauron on their own, without any 'divine' assistance. Though the power of the Elves especially had far diminished from that time, the West still had the ability (obviously) to resist Sauron for a while, at least until the Istari could come up with a plan that did not involve using brute force to destroy Sauron. And, I think, that's in line with the idea that maybe the Valar did not wish for any Middle-earth entity to be powerful enough to take down Sauron on their own. After all, the possession of such power could easily lead to ideals of conquest of Middle-earth, such as the Númenóreans fell prey to attempting.