When All Seems Lost — William C. Dietz

THOSE WILLING TO SACRIFICE...
As interstellar war rages, the president of the Confederacy is captured by the Ramanthian enemy and imprisoned in a brutal labor camp. But the aliens don't realize the prize they have taken, since, at the suggestion of young diplomat Christine Vanderveen, all of the captives have agreed to hide his identity -- though she suspects there may be some tempted to reveal the ruse.

...MUST BE WILLING TO DIE.
General Bill Booly has organized an unauthorized rescue, manned by a team of volunteers with nothing to lose -- and headed by Captain Antonio Santana, Vanderveen's former lover, who must try to set aside his personal feelings for the sake of the mission....