Final answer:
The most successful legislative strategies taken by social movements are incremental and gradual changes.
Step-by-step explanation:
When it comes to legislative strategies, social movements that have tended to be most successful are those that take an incremental and gradual approach. These movements focus on passing laws and winning cases in court rather than using confrontational or violent methods. An example is the African American civil rights movement of the 1950s and 1960s, which used peaceful protests, boycotts, and legal challenges to fight for equal rights.