Human: Why did the grandfather clause exempt illiterate whites, but not blacks? Assistant: 
The grandfather clause exempted illiterate whites, but not blacks, from the literacy test. The grandfather clause, which allowed voters to be registered automatically if their grandfather had voted, effectively exempted illiterate whites, but not blacks, from the literacy test. Blacks received the right to vote in 1870 under the Fifteenth Amendment, so almost no African Americans at this time had voting grandfathers because they were among the first generations of African American voters.