The various Creightons have different feelings about the war. Jethro, the youngest, initially shares the excitement of his older brother Tom and cousin Eb, who are under the delusion that war is a a fine business, with all matter of fancy parades and glory in the battlefield:
War meant loud brass music and shining horses ridden by men wearing uniforms finer than any suit in the stores in Newton. (chapter 1)
However, Jethro's mother Ellen is worried about the prospect of war. She knows that she might lose her sons in battle, and therefore she is not enthusiastic about it at all. Matt, her husband, is cool-headed about things and is not excited about war as so many other people are. Jethro, too, becomes subdued when he hears the rest of the family discussing the issue at dinner.
The Creighton family support the North in the war, except for Jethro's older brother, Bill. Although he doesn't glorify war, Bill feels compelled to fight for the South for ideological reasons. Therefore the political divisions between North and South are reflected in the Creighton family as well.