I doubt aliens give a hoot whether Earthlings blow up the planet or not.
Maybe they’ve invested heavily in US bonds. Bernanke is getting all that money from somewhere.
If there are really aliens, it would be a mistake assume we share the same values or motivations. In fact, we would likely not even share the same sense of what is real and what is not, and perhaps they would not even have the same notion of time, or "the present", that we do. In short, who knows what makes them tick.
“I doubt aliens give a hoot whether Earthlings blow up the planet or not.”
Unless perhaps that they ARE Earthlings coming back in time so we don’t blow the planet up before we can come up with the technology that they are using to escape the Earth. (Before we blow it up with our technology!?)
Semi-serious.