On Thursday, the Justice Department charged Julian Assange, the founder of WikiLeaks, with multiple counts of violating the 1917 Espionage Act for his role in publishing tens of thousands of classified military and diplomatic documents in 2010. The indictment supersedes an indictment unsealed in April on narrow grounds of attempting to help an Army private surreptitiously break into a government computer to steal classified and sensitive documents.

The new indictment goes much further. It is a marked escalation in the effort to prosecute Mr. Assange, one that could have a chilling effect on American journalism as it has been practiced for generations. It is aimed straight at the heart of the First Amendment.

The new charges focus on receiving and publishing classified material from a government source. That is something journalists do all the time. They did it with the Pentagon Papers and in countless other cases where the public benefited from learning what was going on behind closed doors, even though the sources may have acted illegally. This is what the First Amendment is designed to protect: the ability of publishers to provide the public with the truth.

President Trump has waged a relentless campaign against the news media, going so far as to repeatedly label it the “enemy of the people.” But with this indictment his administration has moved well beyond dangerous insults to strike at the very foundation of the free press in the United States. The Espionage Act has been used against those who disclose classified information only rarely, for good reason. It has never before been used against a journalist.