The government did prosecute Ellsberg under the Espionage Act. The case was dismissed largely due to prosecutorial misconduct on the government's part, in parti

The government did prosecute Ellsberg under the Espionage Act. The case was dismissed largely due to prosecutorial misconduct on the government's part, in particular apparently illegal wiretaps of Ellsberg, the records of which had "disappeared." The famous case that got decided on its merits around the Pentagon Papers was the case against the New York Times and Washington Post, and even that only really narrowly deals with prior restraint and not the actual right to publish the documents (so it left the door open to just prosecuting them after the fact). Popular opinion is in Ellsberg's corner but the law itself is much trickier. It's another of those things that are often being revealed nowadays as things people believe are bedrock principles of American law that are really more of "conventions," things that just aren't done, until they are. Assange is an even more interesting case, since his position really puts him more in the position of the Times or Post as a publisher. My recollection is that to a significant extent the case hinges upon characterizing his actions as being more of an active participant in the leaking to try to sidestep the freedom of the press issue to some extent.