Maybe slavery was the WMD issue of the 19th century. Of course, regardless of the instigating cause, the confederates fought for independence. All you need to do is explain why independence is such a grotesque evil that it had to be stopped at the cost of a million American lives. Ready... set... GO!
When the reason for your rebellion is the continued subjugation of almost four million people then I suggest that you lose a bit of your moral argument. Still, was the defense of an institution that all y'all keep insisting was dying worth a million lives?