What part of the solution to slavery in the US would you call "solving things very well"? The KKK, cultural division, and continuing racial strife more than a century and a half later-- this is the legacy of the Civil War. War, as a rule, is messy, and creates more messes.
It eradicated slavery, the problem, which was neatly solved.

The mess afterwards was the fault of the democrats and their racist policies.

CR