^ Right now is probably not the best time to say that Korea was a successful US intervention. Although relative to other adventures, it was probably less bad.
What? so it would've been better to let the South fall to the North? Nonsense.
American intervention was justified in Korea.
In fact, we have right now a major economic player, a democracy and a very advanced nation in South Korea. Tens of millions of people were saved from the terrible fate of living under the communist North Korean regime.