What group was most successful in achieving national democratic reform?

The Civil Rights Movement in the United States, particularly during the 1950s and 1960s, was one of the most successful groups in achieving national democratic reform. Leaders like Martin Luther King Jr. and organizations like the NAACP played pivotal roles in advocating for racial equality and voting rights. Their efforts culminated in landmark legislation such as the Civil Rights Act of 1964 and the Voting Rights Act of 1965, which significantly advanced democratic principles by prohibiting discrimination and protecting the voting rights of all citizens.