It’s a mistake to view the South as a monolithic region in terms of its politics. Obviously, there are huge racial differences in the region, but even whites have historically been divided across multiple socioeconomic categories. One was the elite planter-lawyer-doctor-merchant class, the “Bourbons,” who ran Southern politics up until about a half century ago. Another category consisted of the downscale, hardscrabble “Jacksonian” farmers who were the most eager backers of the populist insurgency in the 1890s. And most recently we’ve seen the rise of a “New South” middle class that is based on the energy, defense, and tech industries and that has a lot in common with the Northern GOP.
In each Southern state, there were differing mixtures of these and other groups, and the political alliances also varied on a state by state basis. Over time, all three of these groups have worked their way over to the Republican party. The first was the New South middle class, which is why the first solidly GOP House districts in Dixie (outside Appalachia) were in places like Dallas, Houston, and Tampa. Barry Goldwater won the elite Southern class in 1964 because it was the most staunchly segregationist; it then went for Wallace in 1968 and did not vote Republican consistently until after voting rights disappeared as an issue. The most recent entrant to the GOP coalition is that hardscrabble class of old Jacksonians.
Perry’s central Texas home of Haskell County probably falls into this last category. The populists did well here in 1892, the county voted for Hubert Humphrey over Wallace by a 3:1 margin in 1968, and it did not begin consistently voting for Republican presidential candidates until 2000. So it’s really not a surprise to me that Perry didn’t jump ship until after he planned to leave the state legislature.