The problem with being sure that God is on your side is that you can't change your mind, because God sure isn't going to change His.
There are the further difficulties of building a population out of a diversity of races, each at a different stage of cultural evolution, some in need of restraint, many in need of protection; everywhere a bewildering Babel of tongues.
Many attempts had been made by colonial legislatures to cut off or to tax the importation of slaves.