Often mentioned in this book are the kinds of sacrifices regularly made by the folks at home so that the young men fighting the war would have the supplies they desperately needed. Maybe that's not as much of an issue with easier shipping methods now--I don't know--but the working together to make a positive contribution toward a cause meant a lot to those fighting and helped the ones who were at home but separated from loved ones to get through that time.
Kitty, the main character in the book, struggles with the idea of these sacrifices at times. She resents that she has to give up some creature comforts. But toward the end of the novel she has an epiphany about how things were for the deployed soldiers and sailors.
When she climbed the porch steps, shivering, Kitty thought about the boys who slept outside in the cold. How did they do it? She sat on the top step and looked at her watch. How long could she last out here, a few steps from her own front door? Could she last fifteen minutes?
So maybe it was something like this, only with the presence of extreme danger. Did fear make you warmer? She closed her eyes, imagining that all around her were unseen enemies, and that although she needed to sleep, she also needed to stay alert. She imagined a whistling in the air, a mortar shell coming in, how she'd have to get out of the way and run.
Later her father takes the opportunity to encourage her:
"Those boys are doing their part, every one of them, God love them. And to me, they're all heroes, whether they fall in battle or sit stateside. But you know this, Kitty, sure I've said it often enough: We're all fighting this war, dressed in uniform or not. And where the part of the boys overseas is the fighting and the part of the boy stateside is to do the best job he can do to support them, our job is to remain proud and optimistic. We on the home front have to be the bright place those boys can come to in their minds. And we offer our own kind of ammunition: the belief that they're doing the right thing. We must support them fully in every way we can, and we must wait patiently for them to come home.
"A soldier needs to believe with all his heart in his commander and his mission, and he needs for us to believe in him. How do we show him that we do? Not by mourning the fact that he's there but by celebrating the life we are privileged to lead on account of his sacrifice."