East Tennessee has been very hostile toward the Democratic Party since in 1830s. That has never changed, but perhaps their reasoning does. Just because East Tennessee was staunchly Unionist during the Civil War doesn’t mean that they’d be pro-Civil Rights 100 years later. In fact, representatives from East Tennessee voted against the CRA (including Howard Baker’s stepmother). So it’s not surprising the region held for Goldwater (though he did underperform Nixon by quite a bit).
In fact, although not to the same degree as in Missouri, Kentucky and West Virginia, Goldwater underperformed even Hoover and Landon in the most staunchly Unionist and Republican counties. Asenath Waite, you are right that East Tennesseeans were never anti-racist, but they were equally never
pro-Goldwater. They disliked many aspects of what the Arizona Senator stood for, but according to Kevin Phillips most importantly his alliance with the “Cotton States”. His losses in these counties
were a factor allowing Johnson to comfortably win Tennessee.
One could compare East Tennessee with the Great Plains States, which were settled by pro-Union whites. These mostly originated from the Ozarks, which in turn were settled from Appalachia. Plains whites were and are very anti-civil rights, I imagine more so than
the voting records of local congressmen would imply. Like East Tennessee, the Plains strongly swung against Goldwater. What determined whether places like these held was, plainly, the margins the Republicans had had previously.
Contrast that with ancestral copperhead counties in the north which mostly abandoned the Democrats in the 1920s as soon as they started seeing them as the party of big city immigrants.
Actually, those “Copperhead” counties seldom abandoned the Democrats because of their association with big city immigrants. That would mean most abandoned them with Al Smith in 1928, but in fact the date when most did so was either when:
- they became perceived as too pro-war or anti-German during World War One, or
- they became perceived as too pro-urban (or perhaps insufficiently anti-black) during Roosevelt’s second term from 1937 to 1941