Human divisions would be child's play for any reasonably competent alien overlord to exploit - check the masterful 'Twilight Zone' episode 'The Monsters Are Due on Maple Street' for an example of how that might play out.
Something my father dearly loved is the scientific method, and it's founded in this element of humility. The idea is that you pursue the truth wherever it goes; you need to evidence, and you can - you see if it's repeatable.
For a genre that's about looking to the future, science fiction has sure been looking backwards lately. Nostalgia is what sells best, with readers spending their money on movie tie-in novels and sequels to long-running series.
'Life in space is impossible,' we're warned, and amidst the hypnotic beauty of these heavens, we become painfully aware of what a hostile environment space is, how unforgiving, how unsympathetic to human desires.
Higher levels of technology allow fewer people to do more damage.
British and Canadian sci-fi strikes me as more forward-looking than its American counterpart, as evidenced by the success of Iain M. Banks, Charlie Stross, Robert Charles Wilson, and Cory Doctorow.
