Many reporters covering national security and government policy in Washington these days are taking precautions to keep their sources from becoming casualties in the Obama administration’s war on leaks. They and their remaining government sources often avoid phone conversations and e-mail exchanges, arranging furtive one-on-one meetings instead.

“We have to think more about when we use cellphones, when we use e-mail and when we need to meet sources in person,” said Michael Oreskes, senior managing editor of the Associated Press. “We need to be more and more aware that government can track our work without talking to our reporters, without letting us know.”

These concerns, expressed by numerous journalists I interviewed, are well-founded. Relying on the 1917 Espionage Act, which was rarely invoked before President Obama took office, this administration has secretly used the phone and e-mail records of government officials and reporters to identify and prosecute government sources for national-security stories.

Just two weeks ago, the Justice Department announced that Donald Sachtleben, a former FBI bomb technician who had also worked as a contractor for the bureau, had agreed to plead guilty to “unlawfully disclosing national-defense information relating to a disrupted terrorist plot” in Yemen last year.

“Sachtleben was identified as a suspect in the case of this unauthorized disclosure” to an Associated Press reporter, according to the announcement, “only after toll records for phone numbers related to the reporter were obtained through a subpoena and compared to other evidence collected during the leak investigation.”

Times reporter Scott Shane, whose e-mail traffic with a former CIA officer was subpoenaed and seized, told me that the chilling lesson “is that seemingly innocuous e-mails not containing classified information can be construed as a crime.”

Six government employees and two contractors, including fugitive NSA contractor Edward Snowden, have been prosecuted since 2009 under the Espionage Act for providing information to reporters.

Many of the leakers could be characterized as whistleblowers rather than spies; they publicized actions for which the government should be held accountable. But the Obama administration has drawn a dubious distinction between whistleblowing that reveals bureaucratic waste or fraud, and leaks to the news media about unexamined secret government policies and activities; it punishes the latter as espionage.

After The New York Times published a 2012 story by David Sanger about covert cyberattacks by the United States and Israel against Iran’s nuclear enrichment facilities, federal prosecutors and the FBI questioned scores of officials throughout the government who were identified in computer analyses of phone, text and e-mail records as having contact with Sanger.

“A memo went out from the chief of staff a year ago to White House employees and the intelligence agencies that told people to freeze and retain any e-mail, and presumably phone logs, of communications with me,” Sanger said. As a result, longtime sources no longer talk to him. “They tell me: ‘David, I love you, but don’t e-mail me. Let’s don’t chat until this blows over.’ ”

Sanger, who has worked for the Times in Washington for two decades, said, “This is the most closed, control-freak administration I’ve ever covered.”

“Reporters are interviewing sources through intermediaries now,” Washington Post national news editor Cameron Barr told me, “so the sources can truthfully answer on polygraphs that they didn’t talk to reporters.”

A November presidential memorandum instructed all government departments and agencies to set up pervasive “Insider Threat Programs” to monitor employees with access to classified information and to prevent “unauthorized disclosure,” including to the media.

At the same time, revelations in the documents Snowden provided about the NSA’s collection, storage and searches of phone, text and e-mail data have added to the fear surrounding contacts between reporters and sources.

“People think they’re looking at reporters’ records,” Post national-security reporter Dana Priest told me. “I’m writing fewer things in e-mail. I’m even afraid to tell officials what I want to talk about because it’s all going into one giant computer.”

Will Obama recognize that all this threatens his often-stated but unfulfilled goal of making government more transparent and accountable? None of the Washington news media veterans I talked to were optimistic.

Leonard Downie Jr., a former executive editor of The Washington Post, is a professor of journalism at Arizona State University. This article is based on his report “The Obama Administration and the Press,” forthcoming from the Committee to Protect Journalists. From The Washington Post.