If we accept Martin Luther King, Jr. as the greatest civil rights figure in United States history (and feel free to dispute that if you disagree), then who is the second greatest civil rights figure in United States history?
Like MVP voting in sports, there is no definition regarding what constitutes “most valuable” or in this case “greatest”. You can think in terms of the person’s impact on the law, the person’s impact on the American psyche, or whatever criteria you use to assess the person’s impact in advancing civil rights in the United States.