What Kratman does not present here are answers, and by making that choice he avoids some of the preachiness which weakened his earlier books. He doesn't spend a lot of time exploring the history of America in the next hundred years, but does make it clear that ultimately it took the route of isolationism, militarization, and the creation of an imperial America protecting part of the world and largely withdrawn from the hostile remainder. He avoids endorsing or condemning that strategy while pointing out clearly that it still leads to an inevitable conflict with Islam.
Caliphate is Kratman's most complete and readable novel to date, and also the most approachable for a general audience. It may offend some and it is going to leave any reader with something to think about, but it's also an enjoyable read and ultimately a book which I think ought to be read, so go out and read it.