ON Sunday, the Tel Aviv District Court sentenced Anat Kamm, a 24-year-old journalist and former soldier, to four and a half years in prison for leaking documents containing evidence of what she suspected might be war crimes committed by her commanders.

Uri Blau, a prominent Israeli investigative reporter at Haaretz who received the documents from Ms. Kamm, is now waiting to hear whether the attorney general will indict him.

Meanwhile, the commanders implicated in the leaked documents were cleared by the attorney general, and one was promoted to deputy chief of staff of the Israel Defense Forces.

The verdict sends several chilling messages. To young soldiers it says: shut up, even if you suspect your commanders of violating the law; they will go unpunished and you will go to jail if you leak. To the source it says: no one will protect you; don’t be a self-sacrificing fool. And to the journalist it says: know your place; cover what we tell you to cover, print our news releases, and keep within your bounds.

The sentencing of Ms. Kamm — who has already spent two years under house arrest — marks a watershed in the relationship between the public and the news media in Israel.

Leaks are used by journalists as a matter of course. Journalists routinely meet people like Ms. Kamm — ordinary patriotic soldiers who are horrified by the contrast between their expectations of their country and its actual conduct.

These ordinary patriots are sometimes moved to make shocking revelations about their country’s inner workings. They act out of civic duty and a belief that their compatriots need to know the truth, regardless of what official institutions think the public should know.

Ms. Kamm and Mr. Blau operated by the unwritten code of conduct that has enabled the Israeli press to monitor at least some aspects of the country’s powerful security establishment for the past 63 years. Ms. Kamm did not leak her secrets to an enemy, or even to a foreign journalist. She gave the documents to a fellow Israeli, who consulted his editors, and submitted his article to the military censor, who gave him the go-ahead.

On Sunday, we learned that this code of conduct no longer applies.

Despite the steps Ms. Kamm and Mr. Blau took, the Israeli government has labored over the past year to portray Ms. Kamm as an enemy, initially charging her with espionage. Israel’s largest newspapers jingoistically referred to her as “the soldier spy,” rushing to sensationalize the case at the expense of their own vital interest in press freedom.

The plea bargain which Ms. Kamm eventually struck left her charged with “unauthorized holding and distributing of classified information.” But the memory of the espionage charge and the implied notion that informing the public can somehow be equated with treason will continue to poison the Israeli public sphere for years to come.

It could also serve as a dangerous legal precedent.

Mr. Blau also stands accused of holding classified information without authorization and before the end of the year he might be put on trial simply for doing his job — obtaining information and publishing it in the name of the public interest.

The damage to democratic discourse in Israel caused by the imprisonment of Ms. Kamm and the possible indictment of Mr. Blau will not only affect coverage of the Israeli-Palestinian conflict; it could deal a deadly blow to investigative journalism in Israel, destroying the possibility of scrutinizing any controversial subject of vital public interest.

Indeed, Mr. Blau’s portfolio extends far beyond security matters. In the past, he has published important revelations of potential personal corruption involving major public figures such as the Israeli defense minister, Ehud Barak, and the foreign minister, Avigdor Lieberman.

The judges did not elaborate on how Ms. Kamm’s documents have actively damaged Israel’s security. The verdict does, however, mention the potential damage the documents could have caused, had they fallen into the wrong hands.

But the damage the Tel Aviv District Court has inflicted on Israeli democracy is immediate and concrete. One can’t help but wonder if the safeguarding of Israeli democracy itself is in the wrong hands.

Dimi Reider, a contributor to +972 Magazine, is an Israeli journalist and photographer.