Phineas Finn by Anthony Trollope. The first of the “Palliser Novels”, which I plan to reread in sequence.
Battle Cry of Freedom, by James McPherson. The best one-volume history of the American Civil War, it certainly helps me to think about the question of a “just war”. I have formulated my own answer to the question of why the South lost. At least from mid-1862 and the Emancipation Proclamation, the war was one of liberation. The slave-based social system collapsed wherever the Union armies arrived. Hence, the South could not pursue the best military strategies for an independence movement, temporarily surrendering places to keep an army in the field. Even so, it was a near thing, and many of the gains were thrown away after the defeat of Reconstruction.