The Pentagon Papers? My history classes barely got into the 20th century, let alone the 1970s (I graduated in the late '90s). History was not a well-taught subject, and my impression is that recent developments in standardized testing and whatnot has made it even worse.
Also, unless you're concentrating on journalism, the Pentagon Papers incident is a rather obscure and unimportant event. I wouldn't be surprised if even a well-taught and comprehensive US history class didn't touch on it.
