… Democrats began losing the support of white voters after World War II, particularly in the South. During the civil rights movement, white Southerners left the Democratic Party in droves.
Some scholars have argued that changes in the South’s economy caused the party’s decline there. Since wealthier voters tend to be more conservative, it’s plausible that Southerners’ move to the Republican Party is a reflection of the region’s economic growth.
Other historians, though, have long argued that civil rights legislation supported by President Kennedy and other Washington Democrats led to the party’s loss of power in the South. And a study published this month by the National Bureau of Economic Research, based on more than half a century of newly available polling data, supports that interpretation. CONT.
Max Ehrenfreund, Washington Post