Final answer:
Southern states used literacy tests, poll taxes, and the grandfather clause to prevent Black Americans from voting, which also discouraged poor white voters; these were made illegal by the Voting Rights Act of 1965.
Step-by-step explanation:
The practices implemented by Southern states to prevent Black Americans from voting, which also discouraged poor white voters, included a mix of literacy tests, poll taxes, and the grandfather clause. These mechanisms were forms of systemic racism embedded within Jim Crow laws to disenfranchise African Americans and maintain white supremacy in the political realm. The Voting Rights Act of 1965 rendered these practices illegal, as they were clear violations of the constitutional rights of citizens to participate in elections. Literacy tests required individuals to demonstrate a minimum standard of knowledge, often with African Americans being subjected to more difficult tests. Poll taxes imposed a fee for voting, which was often beyond the means of both African Americans and poor whites. The grandfather clause was established to exempt some white voters from these restrictions if they had voted before, or their ancestors had, prior to Black suffrage.