You certainly cannot consider the outcome of the Korean conflict as negative or a defeat looking at Nork and SoKorea today, or do you?
Also do you know that the U.S. ‘defeat’ in VietNam was political said General Giap CommanderinChief of the NVA ?
Good questions. Neither Korea nor Vietnam were (obviously) total victories. Korea was a stalemate and Vietnam was a loss. In the latter case politics played a huge part, as you noted.
My point is that the United States should have learned something from those conflicts. But evidently we have not. We still cannot conceive of being beaten. So there’s no need for caution on the international scene.
Napoleon had the same problem. And we all know where he ended up.