We assume there is no threat of invasion of any type just because we have not found intelligent beings such as us (at least news made publically known), shouldn't we prepare? I've heard all the fantasy senarios of alien invasions and whatnot that we'd see them from afar first, they wouldn't just materialize from nowhere, or would they? We also assme our science is the lastest and most advanced there is**. Would we have enough times if they found us?
We certainly can't tell them to go away, or given them the finger (like they'd understand), or tell them to "put 'em up bitch".
I agree, it does seems like a national security non-issue...now
**BTW, one of the things that have always gotten my goat is when our scientists claim aliens on Earth couldn't have been here just because our science
proves they can't get here (by orders of magitude
). Is this a joke? They do not live on our science, they have their own. How can we expect their technology to be limited by our known science? Is that not kind of ignorant/arrogant? The world does not revolve around us, metaphorically.
The meaning of life is curiosity; we were put on this planet to explore opportunities.