If the source doesn't have the information yet then you are asking them to steal government secrets, the crime for which is conspiracy to steal government secrets. That's traditionally what spies do, not journalists, which is why the crime exists.
Physical strength is a necessary component of committing a crime in my analogy, and the doctor is supplying it even though they know the person is likely to use it in furtherance of illegal acts. Still it is the doctor's duty to heal their patient, and the patient's responsibility whether to commit more crimes or not. Even though they're helping their patient, the doctor is not conspiring to rob a convenience store.
The crime of conspiracy has two requirements. 1) That two people make an agreement to commit a crime and 2) that at least one person takes an "overt act" in furtherance of the crime.
Count 18 of the indictment [0] charges that Assange and Manning "conspir[ed] to commit computer intrusion." The first condition of agreement was easy to show, they clearly agreed they were going to break into a government system. More challenging are the overt acts: they allege that Manning stole the password hash and sent it to Assange, who tried to break it himself, saying "No luck so far."
So both the analogies of providing medical care and advice are irrelevant here - Assange didn't just provide information, he allegedly actually participated in the "overt acts" of criminal conspiracy by trying to crack the password. In your analogy, the doctor joined the criminal on the heist.
[0] https://www.justice.gov/opa/press-release/file/1165556/downl...
I was specifically responding to the idea that telling someone about a program was furthering a crime. You're arguing a different point. And to me it's completely uninteresting to argue over what USG can technically charge him with, because we already know that USG is adept at crafting and twisting law to justify its own actions.