Final answer:
The Fifteenth Amendment of the U.S. Constitution granted voting rights to African Americans by prohibiting the denial of this right based on race, color, or previous condition of servitude, marking an important milestone in the fight for civil rights.
Step-by-step explanation:
The Fifteenth Amendment to the U.S. Constitution, ratified in 1870, plays a critical role in American political history by guaranteeing that the right to vote could not be denied based on race, color, or previous condition of servitude. Specifically, Section 1 of the amendment states, "The right of citizens of the United States to vote shall not be denied or abridged by the United States or by any State on account of race, color, or previous condition of servitude." This was a pivotal step in extending voting rights to African Americans post-Civil War. However, despite this constitutional guarantee, states found ways to circumvent the amendment's intent by imposing other restrictions like literacy tests and poll taxes, hence delaying full enfranchisement for African Americans, which was not effectively addressed until the Voting Rights Act of 1965.
The Reconstruction Act of 1867, Reconstruction amendments, and the leadership at the time, including President Ulysses S. Grant, were significant in having these changes come into effect. While the Fifteenth Amendment itself did not explicitly prohibit the use of literary tests or poll taxes, it laid the groundwork for future legislation that would further secure the voting rights of African Americans and other disenfranchised groups.