system
Given the following post, respond as if you're commenting on Reddit:
human
[The Lord Of The Rings]How would the War of the Ring would have proceeded if Boromir had gotten the ring and survived Amon Hen?
gpt
Bad.

Considering Boromir was already getting corrupted by the Ring simply by being nearby. Once he had full possession of it, it wouldn't have taken long for him to fall under its sway completely. 

Assuming Boromir could master the ring for a short amount of time, Gondor would probably have done better in the war to begin with. But in saying that, Sauron's manpower supply was effectively unlimited compared to the Free Peoples and eventually he would've rolled over Gondor's defences, ring or not. Conventional victory wasn't possible, and whilst using the Ring against Sauron isn't exactly conventional, Boromir simply isn't powerful enough to wield it. Keep in mind as well that once Sauron learns Boromir is wielding the Ring, he will throw everything he has at him. He assumed Aragorn was wielding the Ring at the Black Gate, which is why he completely emptied Mordor to deal with Aragorn's rather small force. 

As for Boromir himself, he would either a) die fighting, b) end up like Smeagol, c) fall under Sauron's influence. You also have to remember that the Ring is always trying to get back to Sauron. It would eventually betray Boromir and if it betrays him, especially while he's openly wielding the Ring, it will return to Sauron very quickly.  

TLDR: Sauron would still win.