Short Answer 
The Voting Rights Act of 1965 aimed to remove voting barriers for African Americans, such as literacy tests and poll taxes, prevalent in Southern states. Its enforcement led to a significant rise in Black voter registration and participation, surpassing that of white voters by the 21st century, marking a key advancement in civil rights.
Step 1: Understanding the Background
The Voting Rights Act of 1965 was a crucial piece of legislation that aimed to eliminate barriers to voting for African Americans. Before this act, many Southern states used tactics such as literacy tests and poll taxes to suppress Black voter registration. These measures effectively disenfranchised Black voters, despite the rights granted under the Fifteenth Amendment of 1870.
Step 2: The Impact of the Voting Rights Act
The Voting Rights Act made it illegal for states to impose discriminatory practices that hindered African Americans from voting. Organizations and leaders, including figures like Martin Luther King Jr., encouraged Black citizens to register and participate in elections. This mobilization led to a significant increase in African American voter registration across the United States.
Step 3: The Resulting Shift in Voter Registration
Due to the enforcement of the Voting Rights Act and the collective efforts of the Black community, African American voter registration rates began to rise dramatically. By the 21st century, these rates not only improved but eventually surpassed those of white voters. This marked a significant milestone in the ongoing struggle for civil rights and equality in voting.