Final answer:
Most Black voters in the South supported the Republican Party after the Civil War due to their efforts to end slavery and grant civil rights. Over time, as Democrats began to include minorities in their coalition, particularly during the Great Depression, there was a gradual shift in support. By the mid-20th century, a significant realignment had occurred, with African Americans increasingly supporting Democrats.
Step-by-step explanation:
During the Reconstruction era and much of the early 20th century, most Black voters in the South supported the Republican Party. This affiliation arose following the Civil War, as Republicans, the party of Lincoln, led efforts to abolish slavery and provide Blacks with legal rights. However, during the late 19th and early 20th centuries, Southern Democrats sought to prevent African Americans from voting or holding office, which resulted in a significant disenfranchisement of the Black populace.
After the turn of the 20th century, Democratic Party leaders began to court Black voters as part of a new coalition, particularly during the Great Depression. This shift was due in part to efforts by national Democrats to expand their voter base by including African Americans and other minorities into their coalition. Despite the support for Democratic presidential candidates, the South remained largely dominated by Democrats who were more conservative on racial matters, maintaining control by disenfranchising Black voters until changes emerged during the civil rights movement.
By the mid to late 20th century, there was a major political realignment within the United States, with African Americans starting to support the Democratic Party more robustly, a trend that has continued into the present day.