He takes the easy way out on the war theory: It would be awful, of course, so let's not think about it. But think about it. Would historical WWII be possible in today's United States? Introduce the draft and send current US population off to die in Europe? I think you'd see intense levels of political resistance, draft dodging and desertion in the field. Fragmentation means you probably can't unite the whole country…
Of course it always ends in violence. Refragmentation == reemergence of extremism. People asserting stronger identities while technology shrinks the world and brings them into closer economic and information loops is a recipe for conflict.
In the old days you could have crazy ideas and no one on the other side of the world gave a hoot. Today you get storming Inland Regional Centers, Federal lands, or malls.