The Ethos Effect by L. E. Modesitt, Jr.
Two centuries later, after the events of The Parafaith War, Commander Van C. Albert, the resourceful officer who once defeated a larger enemy ship, indirectly caused the loss of a civilian liner. Cleared by the board of inquiry, but an embarrassment to the high command, he finds himself in dead-end assignments. Seriously wounded foiling an assassination, Van awakes from a coma to find that he's been decorated, promoted, and summarily retired. Looking for new employment, Van will find that a simple piloting job turns him into a point man in a conflict that will shake the worlds.