> Even in 1976, Carter did great in the deep south.

Carter was a southern conservative, deeply, overtly Christian, whereas Ford, the accidental President, was a northerner and social moderate.

In any case, Presidential elections are not necessarily the best indicator of political alignment. After all, some were blowouts, such as 1972, 1980, and 1984. On other other hand, note that Lyndon Johnson lost much of the south, except his home state of Texas, despite winning big elsewhere in the country. But for political alignment, you also have to look at local elections, such as state houses.

> The realignment happened in the 1980s, due to economic growth in the south. The south went from being poor and agrarian in the 1930s to being newly industrialized in the 1980s.

This makes no sense, because first, the south is still poorer, and second, the political correlation you're implying simply doesn't exist. Why would wealth and industrialization turn a state Republican when that doesn't appear to be the case anywhere else in the country? To the contrary, at present the rural areas are solidly Republican and the urban areas solidly Democratic.

> The 19th century GOP was a coalition of religious conservatives and protectionist industrialists.

I can't say I'm very familiar with the 19th century GOP, and neither of us was alive in the 19th century, but I don't think you've correctly characterized the 20th century GOP. Moreover, I don't think you can characterize "the party of Lincoln" as socially conservative either.