SOUTHERN STRATEGY
Although the phrase "Southern strategy" is often attributed to Nixon's political strategist Kevin Phillips, he did not originate it but popularized it. In an interview included in a 1970 New York Times article, Phillips stated his analysis based on studies of ethnic voting:
"From now on, the Republicans are never going to get more than 10 to 20 percent of the Negro vote and they don't need any more than that... but Republicans would be shortsighted if they weakened enforcement of the Voting Rights Act. The more Negroes who register as Democrats in the South, the sooner the Negrophobe whites will quit the Democrats and become Republicans. That's where the votes are. Without that prodding from the blacks, the whites will backslide into their old comfortable arrangement with the local Democrats."
- Kevin Phillips, Richard Nixon's political strategist
While Phillips sought to increase Republican power by polarizing ethnic voting in general, and not just to win the white South, the South was by far the biggest prize yielded by his approach. Its success began at the presidential level. Gradually, Southern voters began to elect Republicans to Congress and finally to statewide and local offices, particularly as some legacy segregationist Democrats retired or switched to the GOP...
From 1948 to 1984, the Southern states, for decades a stronghold for the Democrats, became key swing states, providing the popular vote margins in the 1960, 1968 and 1976 elections. During this era, several Republican candidates expressed support for states' rights, a reversal of the position held by southern states prior to the Civil War.
Some political analysts said this term was used in the 20th century as a "code word" to represent opposition to federal enforcement of civil rights for blacks and to federal intervention on their behalf; many individual southerners had opposed passage of the Voting Rights Act.
https://en.wikipedia.org/wiki/Southern_strategy
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The "Southern Strategy" was a cynical attempt by Republican strategists to polarize American politics by promoting voting along racial lines.
By "gerrymandering" and suppressing the "non-white" vote, the Republicans were able to maximize the "white" vote at the local, state and federal levels whereby they secured control of Congress and the White House in 2000 and 2016 despite losing the popular vote!