Shadowed Glory. Morningstar, #5

After a cataclysmic interstellar war that came very close to exterminating humanity, the Daybreak Republic has risen from the ashes and embarked upon a mission to unite hundreds of human colony worlds under its banner, in hopes of preventing a second and final conflict that will complete the destruction of the human race. But not everyone agrees that the empire's ends justify the means. Daybreak has always valued forthright manly behaviour, and prized the right to speak one's mind, but this time Leo Morningstar may have gone too far.
After he challenges government policy publically, in a manner that cannot be ignored, he is hastily reassigned to an experimental starship and sent back to the front lines, with orders to take the offensive against the rebel forces as quickly as possible. But with an unproven starship and superiors who don't trust him, and a powerful rebel fleet bearing down on him, Leo is caught between two fires. And this time, he may be burned.