“There comes a time when we can no longer tell the invaders from the invaded. That is what we call "War.”
“The best evidence that time travel is impossible is the fact that we haven't been invaded by hordes of tourists from the future.”
“We'd thought that we were among the first humans to invade this basin, but humans had invaded everything, everywhere. They didn't have to walk into a place to invade it.”
“Only with absolute fearlessness can we slay the dragons of mediocrity that invade our gardens.”
“When a nation forgets her skill in war, when her religion becomes a mockery, when the whole nation becomes a nation of money-grabbers, then the wild tribes, the barbarians drive in... Who will our invaders be? From whence will they come?”
“We own the country we grow up in, or we are aliens and invaders.”