That is a lie – sort of like “if you like your doctor and your insurance you can keep your doctor and insurance”. The racist Southern Democrats stayed racist Southern Democrats until a different electorate – composed of younger voters and transplants from the North replaced them.
The evidence for this is clear.
The accepted wisdom is that the Democrats hamstrung themselves many years ago, when they passed the Civil Rights Act of 1964, and thereby lost the Solid South forever. It’s a nice story, one that allows everyone to feel good: liberal Democrats, who would like to believe their party was martyred in as noble a cause as there could be, and Clinton-Obama Democrats, who have long cited it as proof that the party needs to move to the right and start appealing to conservative Southern whites again.
The only trouble is, it’s not true.
Yes, the South was never “solid” for Democrats again after 1964, and the party lost five of six presidential elections from 1968 to 1988. But at every other level of government, Democrats remained highly competitive, even dominant, in the South for years to come.
Going into the 1994 elections, Democrats still held 16 of the 30 United States Senate seats from the 15 Southern states (which I define as the 11 states of the Confederacy, plus Kentucky, Maryland, Missouri and West Virginia), and nearly two-thirds of the Southern seats in the House. On a state level, the figures were even more one-sided. Democrats held 12 of the 15 Southern governorships, and 29 of the 30 state legislative chambers.
It’s only in the last two decades that these numbers flipped. In the next Congress, fewer than a third of the South’s representatives will be Democrats; if Mary Landrieu loses her seat in Louisiana, there will be seven Democratic senators in the region. Democrats there will hold four governorships and both chambers in just one legislature.