Describe a Goldwater-Humphrey Voter

[SingingAnalyst]

All of the above sound plausible, but none could describe very many people. I doubt that more than 2-3% of those who voted in both 1964 and 1968 fit this description. (By comparison, I'd estimate about 4-5% of those who voted in both 1968 and 1972 were Nixon-McGovern voters). One thing that makes it hard is that, outside of the Black belt counties in the Deep South in which Blacks were denied the right to vote in 1964, it is hard to find places where Humphrey didn't drop at least 10% from Johnson: Minnesota (9.8%) and DC (3.7%) are the only places I can think of, as well as Detroit (8.6%); these latter two underwent significant demographic changes from 1964-1968. I suspect the same is true for Cambridge, MA (7.8%); most of these places didn't have many Goldwater voters anyway.

I think it was mostly just people who changed their politics or who personally disliked Johnson or Nixon.

The least likely places to find such voters? I'd say AR-KY-NC-TN, all of which saw at least 26-point drops in Dem support from 1964 to 1968.