Final answer:
Lyndon B. Johnson's efforts to protect every citizen's right to vote is best exemplified by his pivotal role in passing the Voting Rights Act of 1965, which removed barriers that had disenfranchised African Americans, and his support for the 24th Amendment, which eradicated the poll tax in federal elections.
Step-by-step explanation:
Lyndon B. Johnson's commitment to securing the voting rights of all Americans is most strongly supported by his leadership in the enactment of the Voting Rights Act of 1965. This landmark legislation aimed to overcome legal barriers at the state and local levels that prevented African Americans from exercising their right to vote as guaranteed under the 15th Amendment to the United States Constitution. By outlawing discriminatory practices such as literacy tests and poll taxes, it significantly widened the franchise and is seen as a pivotal achievement in the civil rights movement.
Moreover, Johnson's legislative skill was instrumental in the passage of other key civil rights legislation, including the Civil Rights Act of 1964, which prohibited discrimination based on race, religion, national origin, and gender in public accommodations, housing, and employment. His support for the 24th Amendment, which abolished the poll tax in federal elections, further solidifies his legacy as a champion of voting rights. The commitment to expanding democratic participation and ensuring equal rights for all citizens was at the heart of Johnson's presidency.