So can people concerned about press freedoms rest easy?

Not quite. For now, the case significantly reduces such concerns because it is outside traditional investigative journalism to help sources try to break passcodes so they can illegally hack into government computers.

But some press freedom advocates say they remain concerned. For one thing, the Justice Department could file a superseding indictment, so there is no guarantee that Espionage Act charges will stay out of the case. Under extradition procedures, however, any additional charges would most likely have to come soon — before Britain decides whether to transfer custody of Mr. Assange.

For another, prosecutors cited details that expanded beyond a narrow focus on cracking the passcode and that sounded like typical activities of a journalist. For example, the indictment talks about efforts to conceal conversations by using a special chat service and deleting certain chat logs. It also says Mr. Assange took a step to help Ms. Manning send him the files, by making a special folder for her to upload files.

And it quotes a purported exchange midway through Ms. Manning’s leaks in which she wrote, “After this upload, that’s all I really have got left,” but Mr. Assange replied, “Curious eyes never run dry in my experience.” Several weeks later, according to the indictment, Ms. Manning copied and sent WikiLeaks the diplomatic cables.

The Justice Department’s inclusion of those details as relevant to the case was cause for worry, said Jameel Jaffer, the executive director of the Knight First Amendment Institute at Columbia University.

“The indictment and the Justice Department’s press release treat everyday journalistic practices as part of a criminal conspiracy,” he said. “Whether the government will be able to establish a violation of the hacking statute remains to be seen, but it’s very troubling that the indictment sweeps in activities that are not just lawful but essential to press freedom — activities like cultivating sources, protecting sources’ identities and communicating with sources securely.”

Could Mr. Assange be charged later in connection with Russia’s election interference?

It would not be easy.

The Espionage Act does not cover the disclosure of unclassified emails like the Democratic messages, so prosecutors would have to come up with a theory in which publishing them violated some other law. Even if they could find one, a 2001 Supreme Court ruling held that the First Amendment did not permit prosecutors to charge people with crimes for publishing or broadcasting information so long as they broke no law in acquiring it — even if their sources had done something illegal to obtain it.