Final answer:
Ralph Abernathy took over leadership of the Poor People's Campaign after Martin Luther King Jr.'s death, though he lacked King's charismatic influence. The civil rights movement involved many other leaders and organizations as well, and it continued striving to protect its achievements over time.
Step-by-step explanation:
After the death of Martin Luther King Jr., it was Ralph Abernathy who inherited the challenging task of leading the Poor People's Campaign. Unlike King, Abernathy lacked certain charismatic traits that could galvanize widespread support. In the broader context of the civil rights movement, multiple other leaders and organizations also played vital roles. The movement was never the effort of a single individual; it encompassed a variety of leaders and groups like the Student Non-Violent Coordinating Committee (SNCC), the Congress of Racial Equality (CORE), and the Southern Christian Leadership Conference (SCLC), among others. Even as federal laws were changed, the movement continued, striving to preserve its gains amidst challenges like the weakening of the Voter Rights Act of 1965.