Below we provide updated data on the southern realignment through the 2012 elections. Continuing gains among white voters has led to an increasingly Republican South (which we count as the 11 states of the Confederacy plus Kentucky and Oklahoma). In return, the image of the national Republican Party has become more closely tied to the South. As Nate Cohn notes, 41 percent of Romney voters in 2012 were from the South and a majority of House Republicans represent Southern districts.
As is well known, the Republican Party’s breakup of the Democratic Solid South occurred first at the presidential level. As seen in the first plot (showing the difference in the Republican Party presidential nominee’s vote share between the South and North), the South voted more Republican than the North starting in 1964 (Goldwater vs. Johnson) and supported Nixon more than the North against both Humphrey in 1968 and McGovern in 1972. Jimmy Carter won more support in the South than the North in both of his elections, but since 1984 the South has voted more Republican than the North in 8 consecutive presidential elections. The trend has been mostly stable since 2000: the South has voted about 10 percentage points more Republican than the North over the last four presidential elections.
Congressional Southern Democrats have traditionally fared better than their party’s presidential nominees, but over time the congressional delegations of Southern states has become increasingly Republican. The plots below show the percentage of Southern and Northern seats in the House and Senate represented by Republicans over time. Two recent elections — 1994 and 2010 — stand out for Republican surges in the South that the Democratic Party was not able to recover in recent elections. The importance of these elections is that they used national party waves to wipe out senior conservative Southern Democrats who could not easily be replaced in later elections. Once those seats flipped Republican, they were unlikely to switch back. After 2012, more than 70% of Southern Representatives and Senators are Republicans, with most of the remaining House Democrats representing majority-minority districts.
Finally, the last vestige of Democratic power in the South has been in the state legislatures, but steady Republican gains here have ended unified Democratic control of all Southern state legislatures (including in the last remaining state — Arkansas — in 2012). In both the upper and lower chambers, Republicans now hold more than 60% of seats in southern state legislatures.