Throughout the book you notice that the reasons for fighting vary from person to person on both sides. Shaara accurately points out that, while people like Chamberlain fought to free the slaves, most Southerners could care less, insisting that the war was a matter of “rights.” While slavery was the right that was most threatened by the North, notice that none of the Southern characters are shown to be blatantly racist, with Lee going so far as to dislike slavery all together.
Politically the relationship is simple: Pickett’s “gentleman’s club” analogy references the US Constitution. The southern states felt that they had the right to leave the United States if they felt it was warranted. So the question is which is more important, the state or the nation? Southerners felt it was the state; Northerners, the nation. It is interesting to note that before the war it was grammatically correct to say “The United States are big” while afterwards it was grammatically correct to say “The United States is big.” See the difference? Largely, it was the fear of losing slavery that caused the South to wish to ‘leave the club.’ The fact that an army was raised to quell this rebellion, marching against its own people, was the final straw for most Southerners – including Lee, who turned down command of said army because he could not stand the thought of leading an attack against his home.
Longstreet had grown up with his uncle, Augustus Longstreet, who was famous throughout South Carolina and Georgia as a writer, professor, and politician. Augustus Longstreet’s views are well recorded, not only on state sovereignty but in defense of slavery as well. Historians are unclear as to James Longstreet’s motivations, but it is conceivable that they were similar to that of his uncle’s. Shaara seems to portray Longstreet's motivations as closer to that of Lee’s: defending his home against invasion. It is interesting to note that after the war Longstreet would defend black-American rights after nearly losing his life in riots with fellow Southerners regarding Reconstruction policies.