"When he sent a manuscript of The Irony of American History to his historian friend Arthur Schlesinger Jr., Schlesinger called Niebuhr's attention to the glaring omission of the Negro: One irony deserving comment somewhere perhaps is the relationship between our democratic and equalitarian pretensions and our treatment of the Negro. This remains, John Quincy Adams called it in 1820, "the great and foul stain upon the North American Union"; and I think you might consider mentioning it.[46] But Niebuhr did not mention it, finding it apparently not a substantial concern. This was a serious failure by an American religious leader often called this nation's greatest theologian. How could anyone be a great theologian and not engage America's greatest moral issue? Unfortunately, white theologians, then and since, have typically ignored the problem of race, or written and spoken about it without urgency, not regarding it as critical for theology or ethics."