 University of North Carolina historian Walter Rucker has written that "the emergence of Robert F Williams contributed to the marked decline in anti-black racial violence in the U.S...After centuries of anti-black violence, African Americans across the country began to defend their communities aggressivelyemploying overt force when necessary.This in turn evoked in whites real fear of black vengeance..." This opened up space for African Americans to use nonviolent demonstration with less fear of deadly reprisal.Of the many civil rights activists who share this view, the most prominent was Rosa Parks.