The very short version:

- The Compromise of 1877 allowed Rutherford B. Hayes (R) to become president in exchange for removing federal troops from the southern states.

- The South quickly passed new Black Codes limiting voting rights.

- In order to compete for white votes in the South, a Lily-White Movement among Republicans removed blacks from power within the party.

- The release of the film Birth of a Nation reignited the Klan.

- The first Great Migration of blacks out of the South began.

- The Democratic Party machine in New York, Tammany Hall - which had supported the 13th Amendment - allows blacks to have some political patronage jobs to court their votes (as it had done previously with immigrant arrivals.)

- By 1924, the Klan had significant support in both parties - both discussed whether to condemn the Klan at their 1924 convention, but neither passed a resolution. The Democratic nominee, John Davis, denounced the Klan which shifted some support to Coolidge. In 1928, Al Smith became the Democratic Party nominee. As Catholic, he was also opposed by the Klan and spoke out against the Klan during his candidacy.

- A very significant shift in the black vote happened during the 12-year presidency of FDR. While Eleanor pushed earlier and harder for equal rights, FDR did sign Executive Orders 8802 and 9346 to prohibit hiring discrimination in the federal government and defense contractors. The Democratic Party platforms also became more outspoken on equality during this time.

- Truman created a Civil Rights Commission and spoke out in favor of its recommendations. He also signed Executive Orders against discrimination and segregation in the civil service and the military.

- When the 1948 Democratic Convention nominated Truman and supported the civil rights plank advocated by Humphrey, 35 southern delegates walked out and formed the Dixiecrats with Strom Thurman as their nominee. Large African-American vote totals in Cleveland and Chicago more than accounted for the slim margin that put Truman over the top to remain President.

- While Eisenhower enforced civil rights - finishing Truman's integration of the military and sending in troops to Little Rock to protect the integration of Central High, and he signed Civil Rights legislation sent him by Congress - he was not publicly out-spoken on the issue.

- Civil rights wasn't a prominent national issue during Kennedy's 1960 campaign, but shortly before the election Kennedy made efforts to help MLK Jr get released from jail in Georgia and called his wife Coretta. Nixon, who at the time had a more established relationship with King, made no call. Similar to Truman, the black votes for Kennedy far exceeded his electoral margin in several key states. Kennedy appointed African Americans to high-level positions, supported school integration, created the Committee on Equal Employment Opportunity, and used federal troops and the Attorney General (Bobby) to enforce civil rights.

- The culmination of the transformation happened during the presidency of LBJ. After Kennedy was assassinated, but before the election in 1964, LBJ signed the Civil Rights Act of 64, sent the FBI to investigate the Freedom Summer murders, and cracked down on the KKK. Meanwhile, the Republicans nominated Goldwater, who said that part of the Civil Rights Act was unconstitutional and campaigned on state's rights and law-and-order. After winning in 1964, LBJ went on to sign the Voting Rights Act of 65 and Fair Housing Act of 68, and appointed more black judges than any president before him including the nomination of Thurgood Marshall to the Supreme Court.

- While the Democratic black vote peaked under LBJ, it remained very high in future elections while Republicans like Nixon and Reagan mirrored Goldwater's Southern Strategy which was successful in delivering to 'the Party of Lincoln' the votes of states that had seceded upon his election.

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Of course, political parties focus on a conglomeration of issues and there were myriad other organizations and people responsible for changing the dynamics of history.