I am not a sceptic tank, thank you very much.
Of course America is an empire, they just don't admit it.
And of course the ACW was a real war. The north just called it ACW to make it look as though it was an internal struggle, but the reality is that the USA invaded and conquered the CSA, which was a separate sovereign nation.
The point is, there are plenty of people in the US who like to make out that the US only ever fights righteous wars of liberation. That just ain't so.
[sits back and waits for the flames...]