It only lasted 1 season (1996-97). It's basically X-Files in the 60's. It's surprisingly good.
Bobby Kennedy: Alien hunter
Howard Hughes: Driven mad by aliens
Jack Ruby: Possessed by an alien host
J. Edgar Hoover: Blackmailed by aliens
Allen Foster Dulles: Alien ally
LBJ: Has alien advisers
Hubert Humphrey: Thwarted by aliens
The show is smart, they did their homework, it's a woo fan's wet dream. Where it falls down is that there is just no charisma. They good guys are nice, the bad guys are bad, but there is no one that you love to love or love to hate. X-Files had Mulder and Scully and Cancer Man. The stars in Dark Skies are competent, but they had no one who can grab and hold the screen.
But it was still a fascinating season, and they had it scripted out to season 5 (which would have taken the show to 9/11).
I found it at my local library (that most Socialist of institutions), if you can get it free or cheap, I most highly recommend it.
http://en.wikipedia.org/wiki/Dark_Skieshttp://www.imdb.com/title/tt0115151/http://www.amazon.com/Dark-Skies-Declassified-Eric-Close/dp/B00465I156