Don't be fooled by the opening battle scene and continuous conflict that drives the story into thinking this is a simple action book. It's tense and fast-paced, yes, but it is also full of moral, psychological, interpersonal, and political conflict. It is a book whose external action deeply considers complicated internal issues.
In my review of the first book in the series, I wrote: This is a gripping, thoughtful, powerful story, one deserving of many thoughtful readers interested in considering how a nation might very easily come apart as seen through the eyes of a young man during his descent from respectable patriot to accidental terrorist--or rise to hero, depending on which side of the state line one stands. That is equally true for this book.
While the first book captured the initial conflict and escalation, this depicts the actual war. That opening battle scene is the federal invasion of Idaho, and the protagonists spend the rest of story as occupied insurgents. In quiet moments they ask themselves (and each other) if they are rebel heroes and true patriots or illegal terrorists killing innocent soldiers, and if and how their tactics matter in that equation. When the action gets hot and heavy, though, all that matters is their love and loyalties to those they know best.
Amidst all the action is a discerning deliberation of the many complex factors involved in armed conflict that wonderfully balances the personal and philosophical. Equally entertaining and sobering.