What is a grandfather clause and what was it purpose with respect to literacy test?

A grandfather clause is a provision in a law that exempts someone or something from the law's requirements if they met certain criteria *before* the law was enacted. The key is that it's based on a pre-existing condition, not on present-day qualifications.

In the context of literacy tests for voting, grandfather clauses were used to disenfranchise Black voters in the Southern United States after the Reconstruction era. These clauses stated that if a person, or their father or grandfather, had been eligible to vote *before* a certain date (usually around the time of the end of Reconstruction), then they were exempt from the new literacy tests and other restrictive voting measures.

The *purpose* of the grandfather clause in this context was to allow white Southerners, who had a history of voting, to continue voting even if they were illiterate. It effectively excluded almost all Black Americans from voting, because most of their ancestors had been enslaved and therefore ineligible to vote before the specified date. This was a blatant attempt to circumvent the 15th Amendment, which prohibited denying the right to vote based on race, color, or previous condition of servitude. Grandfather clauses were eventually ruled unconstitutional by the Supreme Court in *Guinn v. United States* (1915).