Stanley A. McChrystal

My very identity as a soldier came to an abrupt end. I'd been soldiering as long as I'd been shaving. Suddenly I'd been told I could no longer soldier, and it felt as though no one really cared if I ever shaved again.

The historical novelist has to consider what has actually happened, while the SF writer is dealing in possibilities, but they are both in the business of imagining a world unlike our own and yet connected to it.