Militia and troops.

[tmcc]

Ragnarok-X said:

Unfortunally i cant bring a good example, because their has never been a situation of comparable value in history.

Sure you can. What about War of the Worlds, Independence Day, Mars Attacks, and even Terminator. In all cases humans rise to fight and eliminate the alien invaders. Except maybe War of the Worlds were the microbes did it.

Seriously though it brings up an idea. So far we only talk about defense by the dominant intelligent race. Maybe there should be some risk that the invader doesn't get along so well with something living on the planet that they didn't know about ala WotW. Medical technology could reduce this risk.