FBI threatens family over Anderson papers
And they are, so far, hangin' tough.
Two very speculative points here (that I would bet the rent on):
Jack Anderson would have taken a great deal of pride in what his family is doing and also that he threatens the powers that be even from his grave.
The FBI is more worried about embarrassment than they are national security. The material they seek bears more on worries about domestic consumption and not external threats.
Anybody want to take this action?