I have a rule I tell every author who sends me a book to review: I only write good ones. If I don’t care for it, I’ll decline to say anything. I figure it’s not my place to crush someone else’s labor of love. So I ventured into Matthew Bracken’s latest offering, “Foreign Enemies and Traitors,” with a bit of trepidation. After all, I’d written reviews in this magazine for the two prior volumes in his trilogy, “Enemies Foreign and Domestic” (Nov. 2005) and “Domestic Enemies: The Reconquista” (Feb. 2007). I called the former “a thrilling first novel…one that engages,...