This isn't mine but maybe because of this. Don't know if every point is true honestly.
Southern strategy refers to a strategy by Republican Party candidates of gaining political support in the Southern United States by appealing to racism against African Americans.
During the 1950s and 1960s, the African-American Civil Rights Movement achieved significant progress in its push for desegregation in the Southern United States. The Civil Rights Act of 1964 and the Voting Rights Act of 1965, in particular, largely dismantled the system of Jim Crow laws that had enforced legal (or de jure) segregation in the South since the end of Reconstruction Era. During this period, Republican politicians such as Presidential candidate Richard Nixon worked to attract southern white conservative voters (most of whom had traditionally supported the Democratic Party) to the Republican Party,[4] and Senator Barry Goldwater won the five formerly Confederate states of the Deep South: (Alabama, Georgia, Louisiana, Mississippi, and South Carolina) in the 1964 presidential election. In the 1968 presidential campaign, Nixon won Florida, South Carolina, North Carolina, Virginia, and Tennessee, all former Confederate states, contributing to the electoral realignment that saw many white, southern voters shift allegiance from the Democratic Party to the Republican Party during this period.
ALso
Rewind to the early to mid 1800s: Democrats (Confederates during the Civil War, 1861-1865) dominated the South. Democratic President Andrew Jackson signed the Indian Removal Act of 1830 and shut down the national bank in 1833. It was Democrats who favored limited government, championed manifest destiny and fought to preserve slavery.
The Republican party was formed in the North out of an opposition to slavery in 1854, but it wasnt only abolition they stood for. The party favored expansionist government policies like a national currency, high tariffs to protect fledgling industries and increased spending to fund the railroads and a state university system.
Fast forward to today: the map is reversed, with pro-regulation and pro-welfare Democrats in the West and Northeast, and free-market, limited-intervention Republicans in the South and Midwest.
So when did the switch happen, and why?
Sometime in that window, Republicans went from being the party of government expansion to the party vehemently opposed to FDRs New Deal. But it wasnt an immediate transitionthere were a few decades at the turn of the century when both parties advocated an increased role of the federal government.
Rauchway credits the Democrats ideological shift to their ambitions to win the Western votes that were up for grabs in the post-Civil-War era. Much of the Republican federal expansions of the late 1800s had benefited interests in the Northeastrailroad companies, banks,and other big businesseswhile small-time farmers in the West received little attention. Republicans and Democrats alike tried to woo Western voters with federal support, but Democrats ultimately stuck to a platform of helping out the little guy, while Republicans eventually transitioned to a non-interventionist approach that favored big business.
Although modern Republican and Democratic ideologies had developed by 1936, state loyalties continued shifting for many years after. In fact, only two statesMaine and Vermontvoted Republican in the 1936 election, and in 1972, every state but Massachusetts voted red.
One of the largest shifts in voting patterns occurred in 1964, during what many scholars call the Southern realignmentwhen white Southern voters, likely motivated by race, abandoned the Democrats to vote for Republican Barry Goldwater. Other scholars say that it wasnt race, but an up-and-coming generation of Southern voters joining the Republican party who shifted the tides.
While its difficult to explain the shift in each states party preferences, Rauchway points out one thing thats stayed the same over the years: Although the rhetoric and to a degree the policies of the parties do switch places, their core supporters dontwhich is to say, the Republicans remain, throughout, the party of bigger businesses; its just that in the earlier era bigger businesses want bigger government and in the later era they dont.
http://us-presidents.insidegov.com/stories/3613/republicans-democrats-switch-platform