I've linked to Making of America Books before; it's an online collection of more than 10,000 e-books from the 19th and early 20th centuries, most of which have some historical, social, or cultural interest, and all of which were published in the US. You can now browse their archive by subject, and though there's a lot of chaff (collected sermons, patriotic poetry, treatises on homeopathy), there's plenty of wheat. Just try browsing the subjects "Civil War," "Slavery," or "Immigration."
Hint: When you click on a subject (say, "Abolitionists"), you'll see the various books available on it. Choose one that looks interesting and then click on "List of All Pages." From there go to the book's first Table of Contents page. I've already done that for the books I've linked to.
The US has always had its pacifists; I'm currently reading an anti-Mexican War book titled The War with Mexico Reviewed, by a high-minded Bostonian who makes most of the points anti-war activists make today. Noticeably absent from most of today's pacifist arguments: the author's insistence that making war is not Christian behavior.
For more arguments that haven't changed much for the last 150 years, check out the anti-capital punishment book The Gallows, the Prison, and the Poor-House, by another do-gooder. Again, the religious argument wouldn't be made today, but all the rest of them still are.
More arguments that are still the same: English Items, or Microscopic Views of England and Englishmen, contains some lovely Nativist anti-English invective, along with a long refutation of anti-American stereotypes common in England. In case you hadn't guessed, we were vulgar, ill-mannered, badly educated, uncultured, money-obsessed, and practical to the exclusion of all higher thoughts back then, too, besides being dangerously warlike and imperialistic. One snooty English complaint that is no longer made: Americans spit tobacco juice all over everything.
The Great Riots of New York, 1712 to 1873, is totally awesome, not least for its apocalyptic ultra-reactionary tone. Don't miss the section on the New York Draft Riot of 1863, the closest thing to a Paris Commune we ever had in the States.
Anyone interested in swindles and con games ought to look at The Diddler; most of the scams out there were invented a very long time ago.
The Reformed Gambler is another look at the world of the grifter, written as a rather fantastic autobiography full of unlikely adventures. Wanderings of a Vagabond is similar, though much less moralistic. Both are good stuff, and probably tell you more about everyday life 150 years ago than any textbook could.
Baseball fans should check out America's National Game by Al Spalding, an early star who set up the sporting-goods company that is still in business.
The Longshoremen is an analysis by a group of early social workers of the lives of waterfront workers in New York, a must-read for those interested in labor history in the US.
For a thoroughly disgraceful exaltation of the Ku Klux Klan, including several allegedly funny stories about ignorant Negroes, read K.K.K. Sketches, Humorous and Didactic.
Probably some of you guys need to read Self-Enervation: Its Consequences and Treatment.