This is quite dangerous -- imagine an agent giving someone a document with security markings removed. That person then publishes the document and can now be prosecuted...
If Bob buys a beer and hands it to Larry who then gives it to underage Tommy, we still say you can't do that. But if I leak confidential documents to one person who then goes on to publish them, it's not wrong to publish them?<p>It's still wrong, and should be against the law, no matter how many times removed the action is. Just because people don't like or trust the government does not make it okay to go around publishing documents in the name of free speech.