I’ve just had this idea running through my head. It’s not particularly original, but I feel that it has yet to be done properly.
Let’s assume that the expanding edge of an interstellar empire brushes against Earth. Now, Earth really doesn’t have that much to interest an alien race with FTL technology. There are masses of planets like Earth and Mars out there (in universe) without troublesome natives. Earth’s tech really isn’t advanced enough to interest them (at least those aliens who aren’t interested in cooing over the equivalent of tomahawks and basic ploughs). They don’t really want to invade Earth and they don’t want to commit genocide to eliminate a troublesome barbaric race that can’t even get into space to stay.
What they do want is the solar system. So they move in and explain to Earth that they’ve claimed the gas giants, the asteroids and the comets – oh, and the moon as well. Gas giants are for fuel mining (HE3 would perhaps be the backbone of the galactic economy), asteroids for metals, comets for water-ice…etc, etc. Now, under galactic law, Earth (the US in particular) technically owns the moon, on the grounds the US landed on it first. Obviously, all the morons who think that the stuff floating around in space shouldn’t be claimed for nationalist or commercial reasons will have a cow over this, but the aliens don’t really give a damn. The human race has no way of enforcing its laws over the aliens; Galactic Law basically only recognises power and convention – “if you can’t enforce your laws, tough shit, you’re under our laws and we will happily enforce them with as many rocks as necessary to teach the stupid primitives a lesson. You’re too dumb to put a permanent presence on your own moon – you had your chance, stupid.”
So this particular bunch of aliens gives the US a small amount of alien tech in exchange for accepting that the aliens have taken the moon. When the US balks, the aliens drop a couple of KEWs on military targets (mass slaughter of defenceless civilians is frowned upon by Galactic Law). The good news is that the tech the aliens give the US is basically clean nuclear power and super-batteries and maybe a handful of other tricks. They’re also willing to trade small amounts of tech or raw materials from space in exchange for Earth-made goods and suchlike that they can produce for themselves, but don’t want to waste time doing it (kind-of like how China makes many computers for American markets).
A handful of humans have accepted employment with the aliens, doing various jobs for them (basically, menial jobs; not the sort of thing you really want). Others have been looking for ways to hit back at the aliens.
Anyway, I’m still thinking about ideas for this universe. One would be Earth’s development of a space capability of its own, although that has been done. Another would be trying to find a way to integrate Earth into the alien system so that humans get some basic rights – a small and poor planet, but one with prospects instead of being stuck at the bottom of a gravity well.