I'm just a bit lost with what your point is. Let me try and rephrase...
If we want to figure out which party - of today - would likely be supporting the Civil rights act, all we have to do is see which party represents the most folks from the North and which party represents the most folks from the South.
As it stands:
Democrats - North
Republicans - South
.
You may enjoy reading this link..
The Democrat Race Lie | Black & Right
You're missing my point, as ultimately I am saying "f" the parties and labels; if we're going to talk about civil rights (especially when it comes to blacks) we need to look no further than what region the Congressperson was representing at the time of the vote.
If he/she represents the south, then generally he/she has voted against civil rights. If he/she represents the north, then generally he/she has voted in favor of civil rights. Get my point?
As I understand it, in the early 1900's - for example - the Republican Party represented a
greater number of northern folk than it does today. Therefore, it had generally voted in favor of black rights.
But that has since changed, and now the Republicans are generally supported by a greater number of southern states.
The democraphic that makes up the Republican Party has changed over time, and therefore the overall party's values have ultimately changed (better in some ways, worse in others).