A great read
I just finished reading Lincoln's Speech at Peoria (1854), given as part of the Lincoln-Douglas Debates. I was moved to read it in its entirety from an internet piece referring to Kermit Gosnell as the modern equivalent of a slave-dealer, whom Lincoln noted in his speech was necessary to the southern economy but nevertheless reviled and shunned by southerners themselves. If that comparison eludes you, the original is here: http://www.thepublicdiscourse.com/2013/05/10155/
In any case, Lincoln's speech is great stuff. They spoke for hours at a time back then, but though Lincoln's text is substantial, it's not just full of anecdote and accusation, as so much of our political discourse is today. Lincoln respected his hearers' intelligence, and he assumed that they could, and would, follow a long, sustained argument. Would that politicians today would respect the people enough to lay out their cases as he did.
I also note that reading Lincoln's speech is a better way to understand the blow-by-blow of 19th Century American history than reading the typical history book that goes over the same ground. Lincoln not only tells the story, he sustains the reader's interest better.
If you're into such things, here's a link to the text: http://quod.lib.umich.edu/cgi/t/text/text-idx?c=lincoln;cc=lincoln;rgn=div2;view=text;idno=lincoln2;node=lincoln2:282.1