The excerpt you provided is from the Supreme Court case Guinn v. United States (1915), which dealt with the issue of voting rights and literacy tests in the context of racial discrimination. The case involved a challenge to an Oklahoma law that imposed literacy tests as a prerequisite for voting, effectively disenfranchising many African American voters.
The passage highlights the problematic nature of the literacy test standard established by the law. Although the text does not explicitly mention racial exclusion, it points out that the reliance on a voter’s status before the Fifteenth Amendment inherently created a discriminatory effect. By limiting the voting rights to individuals who could demonstrate entitlement to vote prior to 1866, the law effectively excluded African Americans, who had been enslaved and denied the right to vote at that time.
The Court's decision in this case ultimately established that such standards and requirements for voting were unconstitutional if they resulted in racial discrimination, reinforcing the protections provided by the Fifteenth Amendment. The case was significant in the broader struggle for civil rights and suffrage, as it underscored the need to eliminate laws that perpetuated racial discrimination in voting.