system
Given the following post, respond as if you're commenting on Reddit:
human
[Lord of The Rings] Why didn't the White Council follow up on Sauron after they chased him out of Dol Goldur? Especially seeing as he went to the most obvious place in Middle Earth, his old stomping grounds in Mordor?
gpt
Primarily, Saruman, leader of the White Council, had become corrupt with a desire to have the ring for himself and misled the council with false advice. After Sauron openly revealed himself in Mordor, the White Council, in its last meeting, debated what to do. Saruman claimed that the One Ring was lost forever and that Sauron was no real threat.

At this time the White Council consisted only of Elves and Istari. The Elves were on their way out and the role of the Istari was to be advisory and not to take full control. With the Dwarves being increasingly isolationist, it fell to Men to deal with Sauron.

Unfortunately, only Saruman had a good relationship with men, which he exploited to seize control of Isengard and its Palintir (with which Sauron exert his control over Saruman). Gandalf was manly involved with the Elves and Hobbits (specifically Bilbo and his ring) and his interactions with Men was often luke warm. The other Istari did not factor into the stories of Men (or at least not the Men of the West).

So there really wasn't anyone save Gondor to deal with Sauron, and that was a gradually losing battle.