Actually, that was February 3. 1959.
I think that Wretchard is saying the dreams of liberals may have died some time in the 1970's, in a way that's akin to the plane crash that you mention.
I think he's right. I might put the date as the day the hostages were taken in Iran -- the day Carter and democratic foreign policy started to look impotent when faced with threats from Islamo-fascists.