 Why are the aliens not sure if they can help the humans?
But this vast distance did not mean that isolation could endure forever. Instruments within the ship intercepted radio broadcasts and, within the hour, early TV signals. The history of the planet was tabulated as facts became available. A meteor shower could pass over and their clumsy instruments could interpret it as an all-out enemy attack." They went much closer to Earth, not intending to commit themselves. For a day they circled the planet, avoiding radar detection, which for them was not difficult, testing, and sampling. "What's worse is that I now find they also have missiles, range one thousand miles and upward. They either have or are near a primitive form of space travel." We can't help them," said Ethaniel.
 They do not think they have enough time to intervene like they wish they could
 Their superiors would not approve of an intervention on this planet  They do not think they have enough time to intervene like they wish they could  They do not have experience with this specific type of military technology  They have no way of communicating with the humans in their own languages