WASHINGTON (CN) – In the nearly 100 years since enactment of the 1918 Espionage Act, the government has chosen – out of respect for press freedom – not to prosecute journalists.

That harmony skipped a beat last week, however, when the Justice Department announced it would review media-subpoena policies to address the leaky faucet of classified leaks.

Although Deputy Attorney General Rod Rosenstein wasted little time in walking back the agency’s Aug. 4 announcement, saying Sunday that the DOJ won’t prosecute journalists, national-security attorney Mark Zaid warned that this policy choice should not be mistaken for a legal one.

The Espionage Act “absolutely allows” for the criminal prosecution of journalists, Zaid said. “There’s no exception at all that would give any type of cover legally under the First Amendment, or statutorily, for journalists,” he added.

Zaid, a Washington attorney who represents government whistleblowers at Mark S. Zaid & Associates, would not deny that the government has a right to pursue classified leaks.

“It’s a crime,” he said. “It should be investigated.”

Where the attorney needs convincing, however, is that the Trump administration can break new ground when it comes to pursuing leaks.

Though the Justice Department reported that leak investigations have tripled in the last six months, Trump has a long way to go to catch up with his predecessor.

The Obama administration used the Espionage Act to pursue eight leak cases – more than all other administrations combined – including several that swept up journalists.

In addition to secretly subpoenaing the emails and phone records of Associated Press journalists, the Obama Justice Department labeled Fox News reporter James Rosen an unindicted co-conspirator in one leak case.

And in a hold-over case from the George W. Bush administration, the DOJ in 2011 renewed a subpoena for New York Times journalist James Risen to testify in the leak trial of former CIA officer Jeffrey Sterling. The DOJ dropped the subpoena after Risen refused to identify his sources, but these cases provoked a backlash from journalism and civil-rights groups that viewed them as a war on press freedom.

After the New York Times reported on the secret subpoena of AP records, Zaid said, the DOJ “had egg on their face.” This prompted then-Attorney General Eric Holder to tighten up media-subpoena policies, making it more difficult for prosecutors to pursue media-leak investigations.

Holder’s policies are the very ones that Attorney General Jeff Sessions scheduled last week for review. Still, Zaid said, the agency is free to pivot.

“They’re policies, they’re guidelines,” Zaid said. “The Justice Department could always change them whenever it wants.”

Skeptical of claims that the leaks have heralded a so-called war on the press, Zaid noted that U.S. journalists and newspapers aren’t being raided or shut down.

It would concern him though if the DOJ decides to only investigate leaks embarrassing to the Trump administration from publications viewed as anti-Trump.

“People leak to Fox News classified information,” he said. “Are any of those stories going to be investigated or is it only going to be The New York Times and Washington Post?”

Plotting a Course for Uncharted Waters

While the First Amendment contains an explicit protection for the freedom of the press, the University of North Carolina’s Michael Gerhardt said the guarantees of that protection has always been a moving target.

“Coming up with a definition of the press that works with the Constitution has taken time,” said Gerhardt, a professor of constitutional law, in a phone interview. “It’s been a challenge, and it ends up being broadly defined, but the Supreme Court has not had a lot of press-freedom cases.”

In the Pentagon Papers case, the Supreme Court held that the government’s bid to stop The New York Times and The Washington Post from publishing classified information about the Vietnam War amounted to unconstitutional prior restraint.

Zaid, the national-security attorney, said that case set a high burden for the government to block the publication of information via civil injunction. Against this backdrop, however, Zaid noted that four Supreme Court justices indicated that their decision might have been different had the papers been criminally prosecuted under the Espionage Act.

“The act is pretty clear – publishing classified information without authorization is a criminal act,” Zaid said. “That’s different from civilly getting an injunction under what the First Amendment rights are.”

But Gerhardt said the cases become more complicated when the government can show a need to force journalists to identify anonymous sources. Journalists have often lost those court battles, he said.

Gerhardt pointed to the Supreme Court’s 1972 decision in Branzburg v. Hayes, which held that the government can require reporters to identify their sources and that no special privilege allows them to refuse.

David Schulz, the co-director of the Media Freedom and Information Access Clinic at the Yale Law School, meanwhile noted that Branzburg did not involve a classified leak. In that case, reporters who got in with drug manufacturers and the Black Panthers refused to turn over sources when the groups later came under criminal investigation.

What the case means now is less clear than it would seem, Schulz said.

“Branzburg is key because that’s the only time the Supreme Court has dealt with the issue and there’s quite a heated debate about what the significance of the decision was,” Schulz said in a phone interview.

In the decades since Branzburg, 49 states and the District of Columbia have adopted shield laws that protect journalists from prosecutors who might subpoena them to provide information in criminal trials.

Without a federal shield law, however, reporters in U.S. criminal cases do not have the same protections as state defendants.

“Since that decision, which is over 40 years ago now, most of the circuits in the country have recognized reporter privilege in various contexts,” Schulz said. “It’s still hotly debated.”

A Cauldron in the Beltway

If the DOJ cracks down on leakers, Schulz said to keep an eye on the D.C. Circuit, which heard an important press-freedom case involving former New York Times reporter Judith Miller, who tried to escape testifying before a grand jury investigating the outing of CIA operative Valerie Plame.

The circuit found against Miller and Time magazine reporter Matthew Cooper, holding that no First Amendment privilege protects reporters from giving up their sources. After spending time in prison for contempt of court, Miller testified before the grand jury, which ultimately led to the trial and conviction of Scooter Libby, former Vice President Dick Cheney’s chief of staff.

Schulz highlighted that the D.C. Circuit’s three-judge panel produced four separate opinions on the case. Though concurring, the opinions signify that the case is not as decisive as it might seem.

U.S. Circuit Judge David Tatel’s lengthy fourth concurrence could be of particular importance, Schulz said, should the DOJ subpoena journalists during its investigations of classified leaks.

Tatel likened reporters’ privilege to that of mental health professionals or spouses, but found that it is one the government can overcome by showing that public interest in punishing a leaker outweighs damage to press freedom.

“If litigants and investigators could easily discover journalists’ sources, the press’s truth-seeking function would be severely impaired,” Tatel wrote in 2005. “Reporters could reprint government statements, but not ferret out underlying disagreements among officials; they could cover public governmental actions but they would have great difficulty getting potential whistleblowers to talk about government misdeeds; they could report arrest statistics but not garner first-hand information about the criminal underworld.”

Tatel saw the protection of anonymous sources as key to a functioning press but allowed there are some cases where the interest in protecting classified information is more important, giving the example of an outlet publishing the details of a nuclear weapon. He also said the public has the right to know about some leaks more than others, calling Plame’s name a leak with “marginal news value” that significantly tipped the scales in the favor of the government in Miller’s case.

Schulz said there is room for the D.C. Circuit to clarify this precedent.

“If subpoenas start being issued to reporters in leaks investigations by the Justice Department in Washington, it seems to me that the Tatel balancing comes back into play,” Schulz said. “And the D.C. Circuit hasn’t decided yet whether it as a court would buy into that or not.”

“The whole issue of common-law privilege is still unresolved in the D.C. Circuit,” he added.

Schulz also wondered if the government will even feel the need to subpoena journalists in leak investigations, considering that advancements in technology might make it so that journalists’ notes are not as valuable as they once were. When law enforcement arrested former government contractor Reality Winner in relation to The Intercept’s publication of a leaked classified report on Russia’s attempts to influence the 2016 election, for example, they relied on computer records showing that she was one of six people with access to the document and that she had contacted the outlet over personal email.

Zaid, the national-security attorney, pointed to advances in technology as something that makes journalists more vulnerable to a DOJ policy change on media subpoenas. Just as technology makes it easier to identify the source of leaks, it also makes it easier to identify their recipients.

“I’ve always said that at some point in time I do think a journalist is going to be prosecuted under the Espionage Act for publishing classified information,” Zaid said. “But my belief is it will be a case where there are facts that could be interpreted that the journalist solicited information.”

Zaid said he sees journalists soliciting leaks on Twitter without the clarification that they are seeking only unclassified information. And while that might not be enough for prosecution, Zaid said, “it’s not a good practice.”

“Journalists should recognize what the law is, and that disclosure and publication of classified information may have real consequences that they don’t understand,” Zaid said.

Regardless of whether the government faces backlash for going after journalists, Zaid said journalists should be careful and on guard for government officials trying to set them up. If journalists get sloppy and ask a source directly to provide classified information, it could backfire on them.

“If the government goes forward with a criminal prosecution against a journalist, the law is on the government’s side,” Zaid said. “Policy isn’t, but the law is.”