According to Politico's Jonathan Martin, the Democratic South finally died with this month's midterm elections:
For Democrats in the South, the most ominous part of a disastrous year may not be what happened on Election Day but what has happened in the weeks since.
After suffering a historic rout — in which nearly every white Deep South Democrat in the U.S. House was defeated and Republicans took over or gained seats in legislatures across the region — the party’s ranks in Dixie have thinned even further.
In Georgia, Louisiana and Alabama, Democratic state legislators have become Republicans, concluding that there is no future in the party that once dominated the so-called Solid South.
I'd only note that this is the final culmination of a process that began with the 1994 midterm elections, where a large portion of Republican gains that year came from formerly Democratic strongholds in the South. Those voters were not strangers to voting for Republicans; they regularly supported GOP senatorial candidates and were integral to Republican presidential prospects in the 1960s, 1970s, and 1980s. But thanks to tradition and strong party organizations -- "My father was a Democrat, his father was a Democrat, etc." -- these conservative voters held tightly to their Democratic Party identification. Then as is now, it took a major wave election to make those ties irrelevant.
One last thing: This is a testament to the sheer durability of the Democratic South, and in a way, an excellent example of the enduring power of historical legacies. For nearly a century, from 1877 to 1964, the South was a one-party state, for no other reason than that the GOP was the party of the man who destroyed the Confederate dream. The South was Democratic through the Progressive Era of Woodrow Wilson, the New Deal era of Franklin Roosevelt, and was able to withstand the popular, good-natured Republicanism of Dwight Eisenhower. It took the civil-rights movement to create a fissure in the Solid South, and even then, it persisted for another 15 years, as Democrats remained competitive in the region. It wasn't until Ronald Reagan that Southern whites began identifying themselves as Republican, and it wasn't until 1994 that it meant anything on the state and House level. Politics aside, the death of the Democratic South is worth mentioning for its sheer historical significance.
-- Jamelle Bouie