I'm not knowledgeable on that era, but from what I've read on Johnson I've come to understand that pretty much every piece of explicitly or implicitly racist legislation can be traced directly back to precedent set during his administration. Not that America has been anything other than a colonial settler state, but stuff like literacy tests for voting and the attitude of "well, it's not racist because it never mentions race, even if this law was written with the express purpose of harming black people" comes from southerners trying to find loopholes in the emancipation.

If anyone's got some good resources to link me to, I'd much appreciate it