Seven score and ten years ago, Abraham Lincoln delivered what is arguably the greatest speech in American history. Standing on the battlefield of Gettysburg, Lincoln, recognizing that he could neither add nor detract from the struggles of those brave men who had died defending the Union, urged the fractured nation to dedicate itself to the "unfinished work" of the battle -- the vindication of the principle of natural human equality. In only ten sentences, he thus elevated the purpose of the Civil War and made clear the far-reaching implications of the conflict: "that government of the people, by the people, for the people shall not perish from the earth.