Mississippi 1964?

[TDAS04]

Of course Southerers didn't get rid of their Democratic politicians immediately after civil rights.  Local Democrats were firmly in control, and many anti-civil rights Southerners still trusted their local leaders, and the attachment to the Democratic Party wasn't going to die overnight.  The GOP didn't take control of any Southern legislures until the 1990s.

However, it would be a mistake to discount the longstanding effects civil rights had on Deep South voting at the presidential level, and the disrust many in the South obtained for the national Democratic Party.  After Goldwater, the GOP presidential candidate carried the Deep South in each election except for 1968 and 1976.  Even in 1976, Ford defeated Carter among Southern whites (granted, it was mostly the wealthier suburban whites, but still, look at Mississippi, Alabama, and Louisiana.  There were plenty of Wallace-Ford voters).

As for the segregationist Democrats dying off, maybe they mostly remained lifelong Democrats, but I'm not sure if many 80-year-old whites in the most rural parts of Mississippi and Alabama vote Democratic now.