Final answer:
The assassination of Lincoln, lenient policies of President Johnson, rise of the KKK, and the election of 1876 led to the collapse of Reconstruction. Redeemer governments and the 'separate but equal' legal doctrine from Plessy v. Ferguson entrenched systemic racism and the suppression of African American civil rights for decades.
Step-by-step explanation:
The assassination of Abraham Lincoln, the presidency of Andrew Johnson, the rise of the Ku Klux Klan, and the presidential election of 1876 all contributed to the failure of Reconstruction. Lincoln's death led to a leadership void and a shift in Reconstruction policies under Johnson, who was more lenient towards the South. The Ku Klux Klan's violence intimidated Black Americans and suppressed their voting rights. The 1876 election resulted in the Compromise of 1877, which effectively ended Reconstruction by withdrawing federal troops from the South.
Racist redeemer governments in the South worked to disenfranchise and suppress African Americans through policies like Black Codes, poll taxes, literacy tests, and the implementation of Jim Crow laws after the ruling in Plessy v. Ferguson, which established the 'separate but equal' doctrine. This ruling solidified the legality of racial segregation and contributed to the suppression of African Americans' civil rights well into the 20th century.
The failure of Reconstruction reinforced by these developments left African Americans vulnerable to the discriminatory practices that those in power in the South put in place to maintain white supremacy and prevent actual racial integration and equality.