Douglass's insurgent spirit also grew out of his fundamental commitment to America's democratic promise as codified in the Declaration of Independence and the Constitution. Like innumerable oppressed individuals and groups before, during, and after his time, Douglass located much of the inspiration for his activism in the revolutionary legacy of America's founding generation. He saw himself and his life's work as building upon that tradition. Once free, he never tired of drawing upon the natural and necessary links between his people's freedom quest and that of other oppressed groups. Still, for him, the black liberation struggle, given the centrality of blacks to the national experience, epitomized the continuing struggle to realize the ideals of the Revolution. Indeed, the optimism and belief in progress which guided his life flowed from his own remarkable story of upward mobility and middle-class success as well as the inextricably bound histories of African Americans and the young American nation.