All of the above were ways that the south tried to get around the 15th amendment to prevent African American men from voting. By requiring them to pay a high tax or pass a difficult literacy test, many African Americans were unable to meet the requirements and were therefore unable to vote. The grandfather clauses also prevented many African Americans from voting because it allowed only those whose ancestors had voted before 1867 to avoid the literacy tests and poll taxes, and at that time, blacks were not allowed to vote.
