system
Given the following post, respond as if you're commenting on Reddit:
human
[LOTR] Say Sauron suddenly got the One Ring towards the end of the War of the Ring, but just as he gets it, ALL of his human allies from the east and south immediately betray him, and invade Mordor. Could Sauron win?
gpt
Sauron rules through fear, and if he actually got ahold of the one ring it is very unlikely that they would betray him, and if they did, they would likely just go back where they came from. 

That being said, if they did invade Mordor, it is likely they would all be killed. Sauron's orc forces in Mordor were massive ( we dont have exact numbers.) The forces at the black gate completely surrounded the 6000 strong army of men, and the war was also being waged all across middle earth. 

The forces of men, east or west, had no hope of actually killing Sauron if he had the ring, it litterally took an alliance of men and elves and they were didnt stop him until two literal superheros faced Sauron alone on the battlefield. They managed to mortally wound Sauron, but were both killed in the process.

If they did somehow manage to take Mordor, Sauron would have went elsewhere to rally his forces. It is extremely unlikely that that would happen. If Sauron gets the ring at the end of RoTK, he wins 10/10.