Which amendment ensures that the right to vote cannot be denied based on race or previous condition of servitude?

The 15th Amendment is essential in the context of voting rights as it explicitly prohibits the denial of the right to vote based on race, color, or previous condition of servitude. Ratified in 1870, this amendment was a crucial step toward ensuring that the newly freed African American males could participate in elections. By embedding this protection into the Constitution, the amendment aimed to dismantle the legal barriers that had previously restricted voting rights for marginalized groups and to promote equality in the electoral process.

In contrast, the other amendments mentioned pertain to different aspects of civil rights and liberties. The 13th Amendment abolished slavery and involuntary servitude, while the 14th Amendment focuses on citizenship rights and equal protection under the law. The 16th Amendment deals with income tax and does not pertain to voting rights. Therefore, the focus on race and previous servitude in the context of voting uniquely identifies the 15th Amendment as the correct answer.