system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5:Why did the U.S. win the Korean war but lose the Vietnam war?

Or perhaps put in another way: why is there a South Korea, but there isn't a South Vietnam? What made South Korea possible when we just barely made it out of Vietnam before Saigon fell?

EDIT: I was specifically trying to avoid getting into the semantics of "win/lose" in both wars with my comments above. I fully understand that the Korean war is not officially over.

EDIT 2: Apparently, no one read anything I typed above :(
gpt
They're not very good comparison candidates, they're 3,000Km apart with vastly different terrains & political situations. It's also arguable that the USA did not win the Korean war, given the existence of North Korea it would seem to validate the claim that the USA only partially succeeded. Vietnam was much more a war of the USAs own making than something the locals wanted any part of.