Even if they do repent, sin still has real world consequences. So I hope they repent for their souls and eternal lives, but I'm not against executions/life in prison if they are convicted of crimes against humanity/high treason.

I look at it this way. All sin is the same in God's eyes. It's all equal and causes separation between us and Him without Jesus. But, sins have different earthly consequences. And those need to be dealt with here on earth.