I've been immersing myself in the Civil War, and I just finished "Battle Cry of Freedom" by James McPherson. John Hildebrandt, a member of the Erie County Civil War Sesquicentennial Commitee, told me it's the best one-volume history of the war. This seems to be a consensus; the book won a Pulitzer Prize.
My favorite aspect of the book was how it made the politics of the era come alive; the personal attacks and truth-slanting by both sides seemed just like Fox News or MSNBC. In those days (the 1860s), Democrats were in favor of keeping slavery in place and often were lukewarm on pushing the war forward, so partisan politics had real consequences.
For example, when Lincoln was trying to pass through the 13th Amendment, the one that abolished slavery, he wanted to do so with a few Democratic votes. He could have waited a few months until newly elected Republican lawmakers were seated. But then as now, it was apparently important to appear "bipartisan" when pushing through important programs.
Lincoln and his staff targeted "lame duck" Democrats, i.e., those who were leaving office. A dozen of them were subject to "a barrage of blandishments," the book says (chapter 28). "Secretary of State Seward oversaw this lobbying effort. Some congressmen were promised government jobs for themselves or relatives; others received administration favors of one sort or another."
The administration got 16 of 80 House Democrats to vote for the bill, while eight other Democrats were conveniently absent. "This enabled the Amendment to pass with two votes to spare, 119 to 56," the book says.