I would say that the Pentagon Papers case of 1971 - in which the government tried to block the The New York Times and The Washington Post that they obtained from a secret study of how we got involved in the war in Vietnam - that is probably the most important case.
“Its highest point was The Worst Journey in the World. Then you see this decline, and this harking back, using the 19th-century form when we're not in the 19th century. That way of writing a book about the world out there - you just can't do it anymore.”