So what you're saying is southern Democrats, who were racist and opposed to the Civil Rights Act, abandoned their party to join the party that was responsible for not only freeing the slaves but getting that same Act passed? All because of Nixon's "southern strategy"?
Correlation does not imply causation. Nor does your theory negate the simple fact that parties as a whole still have not deviated from what they started as. Adams v Jefferson.
Here is the vote for the 1964 Civil Rights Act. "Southern" is the 11 states that made up the Confederacy and "Northern" is everyone else. The House passed a version, which is the "original House version," and the Senate passed a version and then because the passed versions had to be identical for it to become law (assuming LBJ would sign it) the House passed the exact same version as the Senate did. Lest you think the votes differed greatly on the "original House version" and "final House version," which was the one that had been passed by the Senate, note that the original House version was 290-130 and the final House version was 289-126.
Okay, here are the vote breakdowns, with more commentary afterwards.
The original House version:
- Southern Democrats: 7–87 (7–93%)
- Southern Republicans: 0–10 (0–100%)
- Northern Democrats: 145–9 (94–6%)
- Northern Republicans: 138–24 (85–15%)
The Senate version:
Note that for each of the four groups defined by North/South and House/Senate, a larger percentage of Democrats voted for it than did Republicans.
When they say that the 1964 Civil Rights Act was passed because of the Republicans it doesn't mean that it was all the Republicans doing. Rather it means although the Democrats held a strong majority in both houses, because most of the South was Democrat where damn near no politician was going to vote for the Civil Rights Act regardless of party, they had to get Republican votes outside the South in addition to Democrat votes.
At the end of the Civil War the Republicans were the progressive ones on race and the defeated Confederate Democrat South were not. Over a century that slowly changed. Actually, maybe for the first half century it didn't change at all. It wasn't until 1924 that blacks were even allowed to attend the Democrat convention. But FDR got in and did some things for blacks, and his wife did too (see All In The Family clip below). And in the late 1940s Truman integrated the Army. And in the early 1960s JFK ensured integration in Southern universities. And then in the summer 1964 LBJ got the Civil Rights Act through. And in every POTUS election since then the Democrat candidate got at least 85% of the vote.
If you look at the numbers above you see that in 1964 the Southern representation in both the House and the Senate was about 95% Democrat. And then the 1964 Civil Rights Act was pushed through by Democrat LBJ and the Democratic North along with significant help from the Republican North. And then in short order in the years after that the 95% Democrat South became strongly Republican because they were so pissed off at the Democrats about the 1965 Civil Rights Act. Considering it was a two major party system and there was only one other party to go to, the Republicans were the one to go to.
The idea of the Republicans taking advantage of the Southern annoyance with the Democrats to cultivate Southern votes is what became known as the Southern Strategy. It evolved as a result of the 1965 Civil Rights Act rather than coming before it.
Here is Archie Bunker and Maude's exchange on FDR. They start talking about FDR and blacks at 1:40 although the whole clip is good.