One tendency I have seen in fantasy is that of the building or collapsing of empires/nations/peoples via a colonialist or imperialist method. Recent examples include The House of the Stag by Kage Baker and even Karen Miller’s The Innocent Mage/The Awakened Mage duology, along with a great many epic fantasy series, in which invasions of empires play a prominent role. Villians, thus, tend to be imperialist in nature, interested in one of two things: 1) the subjugation or destruction of a people, and 2) the acquirement of new properties (i.e. land) for an existing or emerging empire. Looking back brings us to The Lord of the Rings, which contains an example of a colonialist extermination/enslavement that ultimately fails, except insomuch as the Hobbits are concerned, since they are not only colonized by the forces of Mordor (or, more specifically, Saruman’s forces, if memory serves me), but also subjugated as a people.
Science fiction, however, has a shifting agenda. Its early and middle-aged works focused heavily, as I have described before, on imperialist or colonial issues, particularly in relation to galactic empires. Some newer works have done much the same, such as Old Man’s War by John Scalzi and a handful of other authors doing what might be called “tribute” works, though no offense is meant by that term. But recent developments seem to point to a more postcolonial approach. By that, I mean that the story deals more with the after effects of a cultural rupture in which the colonist, whoever that might be, has either ceded control to the indigenous body, or collapsed its colonialist structure and turned into something less concerned with matters of empire and more concerned with what you might call “traditional governing.” So, the colonized may not longer be colonized because the colonizer is no longer there, or because power has shifted, for whatever reason, so that the colonialist structure no longer exists (though the latter is, for all intensive purposes, a rarity even in our world). The best example I can think of this occurring is in Tobias S. Buckell’s novel Sly Mongoose, which, while not always directly focused on the fallen empire, manages to offer a science fiction view of the end of empires and what the colonized goes through to survive or re-establish control. There’s a certain brutality to it, because Buckell’s novel is not set in a world that is distant from its colonial past. Other novels, I’m sure, exist, though I have to admit that I am blanking on them at this time.
The point of this is that there seems to be a far more likelihood of postcolonialism existing within science fiction as a theme than there is for fantasy. Fantasy seems to be occupied with the act of colonizing, in some for of another, while science fiction seems to want to dismantle the colonial structure. It seems fitting that fantasy cannot imagine its postcolonial future, and that its cousin genre must do so. One reflects an imagined past, a medieval fantasy (outside of urban fantasy), while the other is almost always looking forward. The genres compliment one another, even if it was never meant for them to do so.