And the thing that enabled us to win, was our willingness to exterminate the entire population of the other side, if that was going to be necessary to win.
There's a reason why the U.S. doesn't fight wars to "win" anymore.
We don't fight wars anymore, period.
Instead, for the last 50+ years we have been doing nothing more than sending our military to take sides in civil wars all over the world. And we've been doing that because our elected leaders in Washington have been selling themselves to foreign interests for all that time.
You can't exterminate the entire population of "the other side" when the whole purpose of a military campaign is to help one side in a civil war get control of "the other side" without destroying the place.