[zentropia]

We don't need slavery today because we have machines. But in the past if an empire didn't practice slavery implied that other empires will conquer you and slave you. So slavery was required for survival. It's today that this debate is clear. In ancient times, the reverse was true.

[mushi]

I think you missed the point here - slavery over which the US fought a civil war was not in ancient times nor did it protect US from becoming enslaved.