When, if ever, are deceptive tactics legally or ethically permissible in journalism?

An old debate over that question has raged anew for the last week, following a prominent scientist’s admission that he duped a libertarian think tank into giving him a cache of private documents.

In mid-February, a handful of blogs began posting files—including a fundraising plan, a budget, an agenda for a board of directors meeting, and minutes from a board meeting—that belonged to The Heartland Institute, a Chicago-based nonprofit that “promotes free market solutions to social and economic problems” and has long opposed environmental regulations to address threats such as manmade climate change. The files had come, according to reports, via an anonymous e-mail from someone calling himself or herself “Heartland Insider.”

Heartland quickly announced that one of the most damning documents, titled, “January 2012 Confidential Memo: 2012 Heartland Climate Strategy,” was fake. In the process, however, it implicitly acknowledged the authenticity of the others, which revealed, among other things, a plan to create a “global warming curriculum for K-12 schools” that would teach students—incorrectly—that “there is a major controversy over whether or not humans are changing the weather.”

Heartland also sent letters to a variety of websites, blogs, and news outlets demanding that they remove the documents and threatening legal action if they did not. Recipients of the letter posted updates noting Heartland’s claim about the falsity of the climate-strategy document, but refused to remove the files.

The story took a shocking turn on February 20 when Peter Gleick, a scientist, writer, and activist, confessed in a Huffington Post article that he was behind the leak. Gleick claimed that an anonymous correspondent had sent him the climate-strategy document (which Heartland later claimed was a fake) in the mail in early January. In an effort to authenticate it, he said he “solicited and received additional materials directly from the Heartland Institute under someone else’s name.” He then forwarded his trove to a group of journalists and bloggers.

In its letters to various websites and media outlets, Heartland said that Gleick had used the name of a board member in order to trick a staffer into sharing the files. Heartland posted a series of screenshots of its correspondence with Gleick, showing that he signed off as a board member, although the specific name he used (as well as the name of the Heartland staffer he contacted) was redacted.

Following Gleick’s confession, journalists, bloggers, and pundits of all stripes let loose a torrent of commentary about the ethics and likely consequences of his actions. Some scolded him. Some applauded. Some said he had hurt the effort to address climate change and eroded trust in climate science. Some said none of it mattered.

For his part, Gleick called his duplicity “a serious lapse of my own professional judgment and ethics,” and apologized to all those affected. He resigned from the American Geophysical Union’s scientific ethics committee, canceled plans to join the board of the National Center for Science Education, and has taken a leave of absence as president of the Pacific Institute, an environmental research center based in Oakland, California, which he helped found in 1987.

Gleick is an expert on water and climate science, so one should really judge his actions in the context of scientific integrity guidelines. Unsurprisingly and not unreasonably, though, many commentators discussed them in a journalistic context as well. Scott Mandia, a scientist and co-founder of the Climate Science Rapid Response Team (which helps reporters find experts in the field), told The Guardian that Gleick “used the same tricks that any investigative reporter uses to uncover the truth.” Conversely, Time’s Bryan Walsh argued, “No reputable investigative reporter — certainly not one who worked at TIME — would be employed for long after obtaining insider information by lying the way Gleick did.”

In a sense, they’re both right.

“What you wouldn’t gather” from the coverage at major newspapers, media watchdog Jim Naureckas pointed out, “is that there is a long and honorable tradition, from Nellie Bly feigning madness to expose mistreatment of the mentally ill to the Chicago Sun-Times’ Mirage Tavern corruption lab, of investigative journalists using false identities to gather information—when the public interest is clear, and there’s no other way to get the story.” Naureckas noted a couple of other famous examples. In 1992, ABC News reporters used false identities to get jobs at a Food Lion grocery store and secretly film improper food-handling practices. In 2007, Harper’s Ken Silverstein’s impersonated a fictitious representative of Turkmenistan to trick a couple of Washington, D.C. lobbying and communications firms into pitching PR plans that he described as an effort to bolster the image of a dictatorial government.

Curtis Brainard is the editor of The Observatory, CJR's online critique of science and environment reporting. Follow him on Twitter @cbrainard.