I have been reading through the series "The Sword Of Truth by Terry Goodkind. Not only is this an excellent series it is also a good way to teach libertarian principles to others. While you will find that most sci-fi and a lot of fantasy (not the harlequin sort) exalt the ideas of freedom, there will always be those that stand up just a bit higher. This series is one of them.
The previous book (or maybe book 6) dealt with communism, this one deals with moral relativism and its resultant pacifism. Yes, sometimes the story suffers a bit for taking on these concepts (as do all such books, think Ayn Rand) but still makes for a good read
From book 8, Naked Empire.
"Land?" Richard spread his arms. "We do not fight for land. We are loyal to an ideal --an ideal of liberty wherever man lives. We dot not guard territory, bleed for a piece of dirt. We don't fight because we love violence. We fight for our freedom as individuals to live our own lives, to pursue our own survival, our own happiness.
"Your unconditional rejection of violence makes you smugly think of yourselves as noble, as enlightened, but in reality it is nothing less than the abject moral capitulation to evil. Unconditional rejection of self-defense, because you think its a supposed surrender to violence, leaves you no resort but begging for mercy or offering appeasement.
"Evil grants no mercy, and to attempt to appease it is nothing more than a piecemeal surrender to it. Surrender to evil is slavery at best, death at worst. Thus your unconditional rejection of violence is really nothing more than embracing death as preferable to life.
"You will achieve what you embrace.
The right, the absolute necessity, of vengeance against anyone who initiates force against you is fundamental to survival. The morality of a people's self-defense is in its defense of each individual's right to life. Its an intolerance of violence, made by real unwavering willingness to crush any who would launch violence against you. The unconditional determination to destroy any who would initiate force against you is an exaltation of the value of life. Refusing to surrender your life to any thug or tyrant who lays claim to it is in fact embracing life itself.