Though the “Solid South” had been a longtime Democratic Party stronghold due to the Democratic Party’s defense of slavery before the American Civil War and segregation for a century thereafter, many white Southern Democrats stopped supporting the party following the civil rights plank of the Democratic campaign in 1948 (triggering the Dixiecrats), the African-American Civil Rights Movement, the passage of the Civil Rights Act of 1964 and Voting Rights Act of 1965, and desegregation.
The strategy was first adopted under future Republican President Richard Nixon and Republican Senator Barry Goldwater in the late 1960s. The strategy was successful in winning 5 formerly Confederate states in both the 1964 and 1968 presidential elections. It contributed to the electoral realignment of some Southern states to the Republican Party, but at the expense of losing more than 90 percent of black voters to the Democratic Party. As the twentieth century came to a close, the Republican Party began attempting to appeal to black voters again, though with little success.
Huey P. Newton, Shirley Chisholm, Andrew Young, and Senator Edward Brooke of Massachusetts had replaced Martin Luther King Jr. as some of the most prominent black leaders. By this point, King had won the Nobel Peace Prize and founded the Southern Christian Leadership Conference. His death was followed by rioting by African Americans in inner-city areas in major cities throughout the country. King’s policy of non-violence had already been challenged by other African-American leaders such as John Lewis and Stokely Carmichael of the Student Nonviolent Coordinating Committee (SNCC). The notion of Black Power advocated by SNCC leaders was quite effective in altering the mood of African-Americans. This attitude did much to raise the expectations of African Americans and also raised racial tensions. Journalists reporting about the demonstrations against the Vietnam War often featured young people engaging in violence or burning draft cards and American flags. There were also many young adults engaged in the drug culture and “free love” (sexual promiscuity), in what was called the “hippie” counter-culture. These actions scandalized many Americans and created a concern about law and order.
With the aid of Harry Dent and South Carolina Senator Strom Thurmond, who had switched parties in 1964, Richard Nixon ran his 1968 campaign on states’ rights and “law and order.” Progressives accused Nixon of pandering to Southern whites, especially with regard to his “states’ rights” and “law and order” stands.
The independent candidacy of George Wallace, former Democratic governor of Alabama, partially negated the Southern strategy. With a much more explicit attack on integration and black civil rights, Wallace won all of Goldwater’s states (except South Carolina), as well as Arkansas and one of North Carolina’s electoral votes. Nixon picked up Virginia, Tennessee, North Carolina, South Carolina and Florida, while Democratic nominee Hubert Humphrey’s only southern state was Texas. Writer Jeffrey Hart who worked on the Nixon campaign as a speechwriter says that Nixon did not have a “Southern Strategy” but “Border State Strategy” as the campaign ceded the Deep South to George Wallace and that the press merely call it a “Southern Strategy” as they are “very lazy”.
In 2005, Republican National Committee chairman Ken Mehlman formally apologized to the NAACP for ignoring the black vote. However, two days after his address to the NAACP he characterized this as a general strategy, not particularly Southern: “It always interests me when people say it was a Southern strategy. The fact is that folks in the North, the South, the East and the West sometimes did this.” 
Some commentators considered the decisive victory of Democratic Senator Barack Obama in the 2008 presidential election and subsequent re-election in 2012 to represent the lessened influence of Southernization in national politics:
Wayne Parent, a political scientist at Louisiana State University, said that “The region’s absence from Mr. Obama’s winning formula means it’s becoming distinctly less important,… The South has moved from being the center of the political universe to being an outside player in presidential politics.”
Thomas Schaller, a political scientist at the University of Maryland, Baltimore County, stated that the Republicans had become “a Southernized party…. They have completely marginalized themselves to a mostly regional party,” noting that he believed Southernization was over and that the South was no longer needed to win national elections.