You've talked about this Southern shift to the Republican party before, citing the New Deal as the start point. However, the reality is that the South overwhelmingly supported FDR and every Democrat running for President,[with the exception of the segragationist Thurmond], until 1964.
After supporting Goldwater's losing effort, the south voted for George Wallace (68), Richard Nixon (72), and Jimmy Carter (76) in the subsquent national elections. Overlay that record with some of the mid-western Republican bedrocks and a different picture emerges.
Some states of the old Confederacy are just now getting around to electing their first Republican governor or US Senator since Reconstruction! One might conclude that the South's voting patterns are as much governed by their own particular views toward race, religion, and flow of Federal dollars as it was any deep pocket of traditional American values.
This never became any sort of avalanche, because the Republicans started nominating "Me Too" types, like Landon and Dewey. But had Taft won the nomination in 1952, many of the Conservative Southerners would have endorsed him. As it was, even though Eisenhower was a Moderate to Liberal, drafted by the Dewey wing, Harry Byrd adopted a policy of "Golden Silence" on the ticket, which was taken to be tacit approval of Virginia Democrats--true Conservatives--voting for Ike over Stevenson.
When Thurmond switched parties in 1964, in support of Barry Goldwater, most other Conservative Democrats remained pat, although many voted for Goldwater in the fall. But the movement had nevertheless started. It gradually gathered momentum, as Reagan began to emerge as Goldwater's successor. The Wallace campaign in 1968 helped lossen the bonds of party sentiment, and the bulk of the Wallace Democrats later became the Reagan Democrats--not only in the South, but in many Northern States, where Wallace had drawn away the Conservative Blue Collar workers, from the Humphrey ticket--although many still remained within the Democratic Party, as did Wallace himself.
I am very conscious of all of this, because I started out as a Conservative Democrat--a great admirer of Harry Byrd and the Conservative organization in Virginia. While as a young lawyer, I was working closely with Goldwater Republicans by 1960--as a founding member of a local group devoted to the Goldwater nomination from December, 1960 on, I did not actually formally become a Republican until about the same time as Strom Thurmond--also to support Goldwater.
Actually, while growing up in the 1950s, I can tell you that throughout that period, the Conservative/Liberal division was much more important to most of us than the party labels. There was a Conservative coalition, across party lines in Congress, which was responsible for most of the good that was done, and for blocking a lot of bad that was otherwise intended.
William Flax