See Julian Assange. What's his case hinge on again, "conspiracy to commit computer intrusion"? Any amount of working with a source would be such a conspiracy.
I respect the process by which journalists are prosecuted in one country
I didn't even look into the laws in this other country I already didn’t respect, journalists there are prosecuted
As it happened there were a few court case back during the cold war where classified military information were published by news paper and the paper ended up in court. Recalling what I read, they made a few tests in order to confirm their conclusion.
1: Did the leaked information exist publicly before the publication. It make no sense to continue demand legal protection for information which is already public.
2: Did the leaked information cause any harm by being leaked. If it can not be demonstrated to have caused harm then the information should not have been classified from the start and thus do not deserve legal protection.
3: Was publicizing the information in the public interests?
This has made prosecuting news papers for publicizing classified information almost impossible.
It have not stopped government from continuing classifying documents, and media publisher could in theory be found guilty, but the bar is set very high,
The first test is also much harder that one might think. Open source intelligence tend to have a lot of information if one know what to look for. Similar, small news paper can often be early in publishing information before more mainstream publishers.
Quite another when regular citizens / journalists are pressed into service to protect the state from embarrassment.
"something" is a word that goes to a core issues of the whole thing. For democracy to function, people need to be able to argue that things are bad ideas.
Say the military classifies a video because it would undermine public support for a war. There should be no punishment for leaking that, as it is information that is relevant to the public - if it would sway their decision making, then it shouldn't be kept from them.
Say the military classifies troop deployments that are irrelevant to all public decision making - leaking that should be punishable.
So to decide if something is punishable or not, we have to deal with a specific issue and make a judgement on whether that specific issue could reasonably have influenced public decision making.