Describe the allusion that Mary Bethune makes in her speech and the purpose of it. "Perhaps the greatest battle is before us, the fight for a new America: fearless, free, united, morally re-armed, in which 12 million Negroes, shoulder to shoulder with their fellow Americans, will strive that this nation under God will have a new birth of freedom, and that government of the people, for the people and by the people shall not perish from the earth. This dream, this idea, this aspiration, this is what American democracy means to me." - America's Town Meeting of the Air, New York City" - November 23, 1939