The press is under serious attack, but not only because President Trump prefers to call it “the enemy of the people” and revoke credentials at will. Waiting in the wings may well be prison terms.

Between 1917 and 2009, only one person was convicted of violating the Espionage Act for leaking classified information to the press. Then the Obama administration came along and prosecuted eight government whistle blowers at a far higher rate than those undertaken by all previous administrations.

The Trump administration continues the trend. On Oct. 18, former FBI agent Terry J. Albury was sentenced to four years in prison for leaking classified information to the press after he became frustrated by the agency’s abuse of immigrants, including racism and xenophobic attitudes. He sent secret FBI files to the media, which published them.

The Espionage Act passed Congress in 1917 just after the United States entered World War I. Legally and constitutionally the act raised an ironic question: How could authorities enforce it in light of the First Amendment? A good deal depended on the “intentions” of the speaker or writer. The old English common-law principle regarding expression was based on “the rule of proximate causation”; that is, the relationship between spoken or written words and subsequent illegal actions.

The first key case before the Supreme Court involved Charles T. Schenck, secretary of the Socialist Party in America, who distributed to draft-eligible men information that advocated opposition to U.S. involvement in WWI. There was no leak to the press, but his conviction was upheld by the Supreme Court. Writing for the court, Justice Oliver Wendell Holmes ruled that a court must decide whether words that a defendant used were “used in such circumstances and are of such a nature as to create a clear and present danger that they will bring about the substantive evils that Congress has a right to prevent.”

During the Obama administration, Thomas Drake, a senior executive at the National Security Agency, discovered misspent funds in “Trailblazer,” a government program involving spying on American citizens. In 2010, after he determined that the project violated Fourth Amendment protections against unreasonable search and seizure, he informed the inspector general of the NSA and the Department of Defense, and the government ended the program at a cost of $1 billion. Because Drake believed that Americans had a right to know about government wrongdoing, he recounted his findings to a Baltimore Sun reporter, Siobhan Gorman. A federal grand jury indicted Drake for violating the Espionage Act for leaking the information to the press. (He pleaded guilty to a misdemeanor and received no jail time.)

One of the most publicized cases occurred in 2011 when Army Pfc. Bradley Manning, now Chelsea Manning, released hundreds of thousands of national security documents and video recordings tapes to WikiLeaks. Like Drake, Manning was indicted for violating the Espionage Act. In 2013, after announcing that she was a woman, Manning was sentenced to 35 years in prison, the longest in a leak case, and dishonorably discharged from the Army. President Barack Obama commuted her sentence, after which Trump, as a presidential candidate, called her an “ungrateful traitor.”

And now Trump and his Department of Justice want to stop leaks of government wrongdoing to the press by intimidating potential whistle blowers like Albury and others. Last month, the Justice Department charged a Treasury Department official with leaking information about former Trump campaign manager Paul Manafort’s secret wire transfers. Other indictments are presumably pending.

So far, no reporters have been targeted. But given the president’s attacks on “fake news,” which is news he does not like or want the public to know, and claims that the press is the “enemy of the people,” the next in line may well be reporters and editors.

Jack Fruchtman teaches constitutional law at Towson University in Maryland.