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.
“Without action, we are going to continue to allow Iran to be a safe harbor for terrorists, see its economy further deteriorate, and see the Middle East further destabilize.”
“Only one thing is impossible for God: To find any sense in any copyright law on the planet.”